Oleksandr Syrskii, Ukraine’s top military commander, has defended Ukraine’s incursion into Russia’s Kursk region, saying the offensive was working because Russia had not advanced on a key area of the eastern front in Ukraine for six days.

Kyiv launched its surprise offensive into Kursk on August 6 and says it has captured an estimated 1,300 square kilometres (502sq miles) of territory and dozens of settlements.

Officials have said the offensive was part of a strategy to slow Russia’s advance towards the strategically important town of Pokrovsk in Donetsk in eastern Ukraine.

Speaking to United States broadcast network, CNN, Syrskii said Ukraine was doing “everything possible not to lose Pokrovsk”.

“Over the past six days, the enemy hasn’t advanced a single metre in the Pokrovsk direction,” he said. “In other words, our strategy is working.”

It was not possible to verify the situation on the front line and the claims made by each side.

Earlier on Thursday, Russian President Vladimir Putin said the Kursk offensive had failed to slow Russia’s advance and that the move had only served to weaken Ukraine’s defences in Donetsk.

Analysts say Russia has moved few soldiers from the Ukrainian east to Kursk, where its forces are supported by conscripts and ethnic Chechen fighters.

It has continued to claim advances towards Pokrovsk, saying it captured several small villages east of Pokrovsk as well as nearby Myrnohrad. Tens of thousands of residents are being evacuated.

In his interview, recorded at an undisclosed location close to the front line, Syrskii acknowledged the situation in Pokrovsk was “the most problematic for us” but insisted the Kursk offensive was having the intended effect.

“We’ve taken away their ability to manoeuvre and deploy reinforcements,” he said.

“We know the amount of artillery shelling as well as the intensity of the offensive has decreased.

“I think this strategy was chosen correctly, and it will bring us the desired result.”

Amid the continued fighting and a new wave of Russian bombardment that has killed dozens over the past week, Ukraine has stepped up pressure on the US and its other allies to provide it with more air defences and allow it to use Western-supplied long-range weapons on military targets inside Russia.

Those issues are likely to be discussed later on Friday when members of the Ukraine Defense Contact Group (UDCG), a group that provides military aid to Ukraine, meet in Germany.

Ahead of the meeting, the United Kingdom announced it would supply 650 lightweight multirole missile (LMM) systems to boost Ukraine’s air defence capabilities with the first deliveries by the end of the year.

“In recent days, we have seen the tragic cost of Russia’s indiscriminate strikes on Poltava and Lviv,” UK Defence Secretary John Healey said in a statement. “These new UK-made missiles will support Ukraine to defend its people, infrastructure and territory from Putin’s brutal attacks.”