KYIV/LONDON/PRAGUE: Ukrainian forces repulsed a Russian attack on Kyiv but "sabotage groups" infiltrated the capital, officials said Saturday, as Ukraine reported 198 civilians deaths, including children, following Russia's invasion.

A defiant Ukrainian President Volodymyr Zelensky vowed his pro-Western country would never give in to the Kremlin even as Russia said it had fired cruise missiles at military targets.

With explosions echoing around Kyiv on the third day of Russia's assault, Zelensky spoke in a video message, wearing olive green military-style clothing and looking tired but determined.

"I am here. We will not lay down any weapons. We will defend our state, because our weapons are our truth," he said.

"Our truth is that this is our land, our country, our children and we will protect all of this."

Ignoring warnings from the West, Russian President Vladimir Putin unleashed a full-scale invasion that the UN refugee agency said has forced almost 116,000 people to flee to neighbouring countries.

Tens of thousands more are estimated to be displaced within Ukraine, with many on the move to less affected western areas of the country.

In Kyiv, residents took shelter in the subway system and in cellars and basements.

"We thought something like this might happen but we were hoping until the end that it wouldn't," Irina Butyak told AFP in one shelter.

"We were hoping that common sense and common decency would prevail. Well, it didn't," said the 38-year-old teacher, who hoped she would be able to escape soon to western Ukraine.

Ukrainian Health Minister Viktor Lyashko said 198 civilians, including three children, had been killed in the conflict and 1,115 wounded.

In Paris, French President Emmanuel Macron warned that the world must brace for a long war.

"This crisis will last, this war will last and all the crises that come with it will have lasting consequences," Macron said.

"We must be prepared".

After speaking to Macron, Zelensky tweeted to thank "partners" for sending weapons and equipment.

Several NATO members have sent weapons and ammunition to Ukraine in recent weeks, including Britain, the United States and ex-communist countries in Eastern Europe.

In another video address, the 44-year-old leader also said that his country had "derailed" the Russian plan of overthrowing him and establishing a puppet state in Ukraine.

Air raid sirens and birdsong

In the early hours of Saturday, AFP reporters in Kyiv heard occasional blasts of what soldiers said were artillery and Grad missiles being fired in an area northwest of the city centre.

There were also loud explosions in the centre.

Emergency services said a high-rise apartment block was hit by shelling overnight, posting a picture that showed a hole covering at least five floors blasted into the side of the building.

Kyiv's mayor, Vitali Klitschko, said the building had been hit by a missile.

"The night was difficult, but there are no Russian troops in the capital," he said.

"The enemy is trying to break into the city, in particular from Gostomel, Zhytomyr, where the aggressors are neutralised," he said, referring to two settlements to the northwest and west of the city.

"Now in Kyiv there are, unfortunately, sabotage groups, there were several clashes," he said.

Hours later, AFP saw a destroyed Ukrainian military truck in the city centre and a civilian volunteer digging a trench for soldiers.

Ukrainian army tanks were also seen manoeuvring all over the centre but the streets were mostly empty and the centre silent except for the sound of air raid sirens and birdsong.

The city said it was toughening a curfew in place and anyone on the streets after 5:00 pm would be considered "members of the enemy's sabotage and reconnaissance groups".

Russian plan 'derailed'

Zelensky on Saturday said that Ukraine had "derailed" Russia's attack plan and urged Russians to pressure Putin into ending the war.

When he announced the assault in a pre-dawn television statement on Thursday, Putin called it a "special military operation" aimed at defending Russia-backed separatists in eastern Ukraine.

The separatists have been fighting Ukrainian government forces in the east for eight years in a conflict in which more than 14,000 people have been killed.

Russia's communications regulator on Saturday told independent media to remove reports describing it as an "assault, invasion, or declaration of war".

In a statement, the regulator accused the media outlets of spreading "untrue information" about the shelling of Ukrainian cities by the Russian army and civilian deaths.

'Point of no return'

But Russia has brushed off international condemnation and increasingly stringent sanctions adopted by the United States, Canada, Britain and the European Union, including against Putin himself and Foreign Minister Sergei Lavrov.

Russia said sanctioning the pair was "a demonstration of the complete impotence of the foreign policy" of the West.

"We have reached the line after which the point of no return begins," Russian foreign ministry spokeswoman Maria Zakharova said.

The impact of sanctions has been far-reaching.

French naval forces on Saturday said they had intercepted in the Channel a cargo vessel loaded with cars bound for Russia.

The Russian-flagged Baltic Leader ship is suspected of belonging to a sanctioned company.

Zelensky has called on Western allies to expel Moscow from the SWIFT banking transfer system.

But a number of EU countries, including Germany, Hungary and Italy, have been reluctant over fears Russia could cut off gas supplies.

While sanctions have focused on Russia-linked finances, travel and trade, there have also been repercussions in the worlds of culture and sports.

In the latest development, Poland on Saturday said it was refusing to play its 2022 World Cup play-off against Russia on March 24.

Earlier updates

Earlier on Saturday, Russian forces captured the southeastern Ukrainian city of Melitopol, Russia's Interfax news agency reported, as Moscow launched coordinated cruise missile and artillery strikes on several cities, including the capital Kyiv.

Ukrainian officials were not immediately available for comment on the fate of Melitopol, a city of about 150,000 people. If confirmed, it would be the first significant population centre the Russians have seized since their invasion began on Thursday.

Ukrainian city of Melitopol not in Russian hands, British minister says

Meanwhile, British armed forces minister James Heappey said on Saturday Russian forces have not captured the southeastern Ukrainian city of Melitopol and armoured columns advancing on the capital Kyiv have been held up by Ukrainian resistance.

Heappey said it was the British assessment that Russia had so far failed to capture any of its day one targets for its invasion of Ukraine, which began on Thursday.

"Even Melitopol, which the Russians are claiming to have taken but we can't see anything to substantiate that, are all still in Ukrainian hands," Heappey told BBC radio.

"The fighting ... reported on the outskirts of Kyiv overnight, we understand to just be Russian special forces and pockets of paratroopers," he said.

"The reality is that the armoured columns that were coming down from Belarus and the north that were going to encircle Kyiv are still some way north because they've been held up by this incredible Ukrainian resistance," the minister said.

Czechs to ship weapons, ammunition worth $8.6mn to Ukraine

Czech government approved sending weapons and ammunition worth 188 million crowns ($8.57 million) to help Ukraine defend itself against Russia's attack, the Czech Defence Ministry said.

The shipment, which includes machine guns, assault rifles and other light weapons, will be delivered by the Czech side to a location picked by Ukraine, the ministry said.

"Our help is not over!" the ministry said on Twitter.

Earlier, Ukrainian officials said Russian forces fired cruise missiles from the Black Sea at Mariupol, as well as Sumy in the northeast and Poltava in the east.

Ukrainian authorities have urged citizens to help defend Kyiv from the advancing Russian forces but even as the fighting grew more intense, the Russian and Ukrainian governments signalled an openness to negotiations, offering the first glimmer of hope for diplomacy since Russian President Vladimir Putin launched the invasion.

The air force command earlier reported heavy fighting near an air base at Vasylkiv southwest of the capital, which it said was under attack from Russian paratroopers.

It said one of its fighters had shot down a Russian transport plane. Reuters could not independently verify the claims.

Heavy fighting in Kyiv outskirts as Russia, Ukraine signal possibility of talks

Mykhailo Podolyak, adviser to the president's office, said the situation in Kyiv and its outskirts was under control.

"There are cases of sabotage and reconnaissance groups working in the city, police and self-defence forces are working efficiently against them," Podolyak said.

Kyiv residents were told by the defence ministry to make petrol bombs to repel the invaders.

Some families cowered in shelters and hundreds of thousands have left their homes to find safety, according to a UN aid official.

Ukraine military says it repels Russian troops' attack on Kyiv bas

Ukraine said more than 1,000 Russian soldiers had been killed. Russia did not release casualty figures. Zelenskiy said late on Thursday that 137 soldiers and civilians been killed with hundreds wounded.

Putin's appeal

After weeks of warnings from Western leaders, Putin unleashed a three-pronged invasion of Ukraine from the north, east and south on Thursday, in an attack that threatened to upend Europe's post-Cold War order.

"I once again appeal to the military personnel of the armed forces of Ukraine: do not allow neo-Nazis and (Ukrainian radical nationalists) to use your children, wives and elders as human shields," Putin said at a televised meeting with Russia's Security Council.

"Take power into your own hands."

Putin has cited the need to "denazify" Ukraine's leadership as one of his main reasons for invasion, accusing it of genocide against Russian-speakers in eastern Ukraine. Kyiv and its Western allies dismiss the accusations as baseless propaganda.

Ukrainians voted overwhelmingly for independence at the fall of the Soviet Union and Kyiv hopes to join NATO and the EU - aspirations that infuriate Moscow.

Putin says Ukraine, a democratic nation of 44 million people, is an illegitimate state carved out of Russia, a view Ukrainians see as aimed at erasing their more than thousand-year history.

Western countries have announced a barrage of sanctions on Russia, including blacklisting its banks and banning technology exports. But they have stopped short of forcing it out of the SWIFT system for international bank payments.

The United States imposed sanctions on Putin, Foreign Minister Sergei Lavrov, Defence Minister Sergei Shoigu and Chief of General Staff Valery Gerasimov. The European Union and Britain earlier froze any assets Putin and Lavrov held in their territory. Canada took similar steps.

The invasion triggered a flurry of credit rating moves on Friday, with S&P lowering Russia's rating to "junk" status, Moody's putting it on review for a downgrade to junk, and S&P and Fitch swiftly cutting Ukraine on default worries.

But amid the chaos of war came a ray of hope.

A spokesman for Zelenskiy said Ukraine and Russia would consult in coming hours on a time and place for talks.

The Kremlin said earlier it offered to meet in the Belarusian capital Minsk after Ukraine expressed a willingness to discuss declaring itself a neutral country while Ukraine had proposed Warsaw as the venue. That, according to Russian spokesman Dmitry Peskov, resulted in a "pause" in contacts.

"Ukraine was and remains ready to talk about a ceasefire and peace," Zelenskiy's spokesman, Sergii Nykyforov, said in a Facebook post. "We agreed to the proposal of the President of the Russian Federation."

But US State Department spokesman Ned Price said Russia's offer was an attempt to conduct diplomacy "at the barrel of a gun" and Putin's military must stop bombing Ukraine if it was serious about negotiations.

At the United Nations, Russia vetoed a draft Security Council resolution that would have deplored its invasion, while China abstained, which Western countries took as proof of Russia's isolation. The United Arab Emirates and India also abstained while the remaining 11 members voted in favour.

The White House asked Congress for $6.4 billion in security and humanitarian aid for the crisis, officials said, and Biden instructed the US State Department to release $350 million in military aid.