Putin, shown in videos visiting a command post and receiving a report from top commanders, praised the city’s capture as an important strategic achievement.

He also said Russian forces had to increase the scale of security zones in response to intensified Ukrainian long-range strikes, mainly ​against Russia’s oil industry.

Ukraine made no comment on Russia’s claim to have seized Kostiantynivka.

General Valery Gerasimov, chief of Russia’s General ​Staff, announced the city’s capture in a report on the conduct of the war, now in its ⁠fifth year.

Gerasimov said the southern group of forces was carrying out offensive operations to “liberate” all of the Donetsk region, part of the ​broader Donbas region over which Russia has vowed to secure control as a key aim of its war effort.

“The troops of the group have ​liberated the city of Kostiantynivka, one of the main defensive hubs of the enemy within the Sloviansk-Kramatorsk-Kostiantynivka fortified area”, Gerasimov said.

Russia’s military has for some time reported that its troops were in control of parts of Kostiantynivka, one of several cities seen as a network of key fortifications in Ukraine’s defence of ​the region.

Putin described the city as having an important strategic significance.

“We all know that this city is a key transport and large ​industrial centre of Donbas,” Putin said.

Soldiers in city

The Defence Ministry posted images on Telegram that it said were scenes from Kostiantynivka, including ‌pictures of ⁠Russian soldiers holding national flags by shattered buildings.

Gerasimov also told Putin that Russian forces were closing in on Lyman, a town about 70 km to the north which he said was “of key logistical and strategic importance for further advances in this direction”.

The head of Russia’s northern troops, Yevgeny Nikiforov, said his forces had “not yet fully managed to resolve the task” of preventing Ukrainian drone strikes that have hit ​oil installations and caused fuel ​shortages in Russia.

Putin responded by ⁠saying: “The more attacks the enemy tries to carry out on our civilian facilities … the larger a security zone we’ll have to establish in the neighbouring territory.”

Nikiforov told Putin that Russian troops were making progress ​in securing border areas in the Kharkiv and Sumy regions, where Moscow has called for expanded ​buffer zones.

Ukrainian President Volodymyr ⁠Zelensky and other officials have said Russia’s advances in eastern Ukraine have slowed considerably since the beginning of the year and Kyiv’s forces have even recaptured some territory.

Putin, in his remarks, dismissed Kyiv’s statements as an “information campaign in which it puts on display supposed successes”.

Zelensky sent an ⁠open letter ​to Putin last month seeking a direct meeting, but the Kremlin leader rejected the ​proposal.

US-brokered attempts to move towards a peace deal have been put on hold during the conflict in Iran, but both Moscow and Kyiv say they are anticipating a ​visit soon by the two top negotiators, Steve Witkoff and Jared Kushner.