KYIV: Russian forces pounded Ukrainian cities including the capital Kyiv with artillery and cruise missiles on Saturday for a third day running and Russia's Interfax news agency said they had captured the southeastern city of Melitopol.

Ukrainian officials were not immediately available to comment on the fate of Melitopol and Britain's armed forces minister James Heappey cast doubt on the report, saying the city of some 150,000 people was still in Ukrainian hands.

"All of Russia's day one objectives ... and 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," he told BBC radio.

Western intelligence sources say Russian forces have encountered far stronger Ukrainian resistance than they had expected and this was significantly slowing their advances since their invasion began on Thursday.

If the Interfax report about Melitopol, which cited Russia's defence ministry, is confirmed, it would be the first significant population centre the Russians have seized.

At least 198 Ukrainians, including three children, have been killed and 1,115 people wounded so far in Russia's invasion, Interfax quoted Ukraine's Health Ministry as saying. It was unclear whether the numbers comprised only civilian casualties.

Kyiv's mayor Vitali Klitschko said 35 people, including two children, were wounded during overnight fighting in the city.

Klitschko said there was currently no major Russian military presence in Kyiv, although he added that saboteur groups were active. The metro system is now working only as a shelter for city residents and trains have stopped running, he said.

There were signs of panic in Kyiv city centre. Reuters reporters saw Ukrainian soldiers with guns and a group of women running along the street. Nearby, Ukrainian soldiers forced a man in civilian clothes to lie down on the pavement.

Earlier, Kyiv authorities said a missile hit a residential building, and a Reuters witness said another hit an area near the airport. There was no immediate word on casualties.

'We will defend our state'

President Volodymyr Zelenskiy, speaking in a video message from outside his Kyiv office, was defiant.

"We will not put down weapons, we will defend our state," he said.

Zelenskiy earlier signalled a readiness to discuss a ceasefire and peace talks, as did the Kremlin, but tentative diplomatic contacts have so far produced no results.

Ukraine has evacuated its embassy staff in Moscow to Latvia, the Baltic country's foreign ministry said on Saturday.

Tens of thousands of Ukrainians were arriving at the country's western borders with Poland, Hungary, Slovakia and Romania. At Medyka in southern Poland, refugees described a 30-km (19-mile) line at the border.

An adviser to Ukraine's Interior Ministry, Anton Herashchenko, said at least 40 civilian infrastructure sites had been hit so far. Moscow says it is taking care not to hit civilian areas.

The mayor of Chernihiv, some 150 km (93 miles) northeast of Kyiv, told citizens: "We need to prepare for street combat. Those of you who know and understand what I am talking about, prepare the petrol bombs."

Fighting was also underway on Saturday morning in the northeastern city of Sumy, the municipal administration said, urging residents to stay at home.

Ignoring weeks of warnings from Western leaders, Russian President Vladimir Putin invaded from the north, east and south, an attack that threatens to upend Europe's post-Cold War order.

Putin said he had to eliminate what he called a serious threat to his country from its smaller neighbour and he cited the need to "denazify" Ukraine's leadership, accusing it of genocide against Russian-speakers in eastern Ukraine.

Kyiv and its Western allies dismiss the accusations as baseless propaganda.

In a televised meeting with Russia's Security Council on Friday, Putin appealed to Ukraine's military to overthrow their "neo-Nazi" leaders.

"Take power into your own hands," he said.

Sanctions

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.

Moscow will respond symetrically to the seizure of money of Russian citizens and companies abroad by seizing the funds of foreigners in Russia, RIA news agency quoted the deputy head of Russia's Security Council, Dmitry Medvedev, as saying on Saturday.

France will provide defensive military equipment to Ukraine, its army spokesman said on Saturday. The Czech government said it was sending weapons and ammunition to Ukraine.

At the United Nations on Friday, Russia vetoed a draft Security Council resolution deploring 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 U.S. State Department to release $350 million in military aid. Read full story

Russia's defence ministry said their forces used air- and ship-based cruise missiles to carry out overnight strikes on military targets in Ukraine, Interfax said.

It said Russian troops had hit hundreds of military infrastructure targets and destroyed several aircraft and dozens of tanks and armoured and artillery vehicles.

Ukraine's air force command earlier said one of its fighters had shot down a Russian transport plane. Reuters could not independently verify the claim.

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.

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.

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 cutting Ukraine on default worries. Read full story