Ukraine’s long-awaited counteroffensive against Russia’s invading army has yet to begin, according to President Volodymyr Zelenskiy, despite his generals claiming some of their largest combat victories in months.

Kyiv claims to have forced Russian soldiers back in small attacks in the eastern city of Bakhmut over the past several days, but a full-fledged counteroffensive involving tens of thousands of troops and hundreds of Western tanks is still being planned.

“We still need a bit more time,” Zelenskiy said in an interview with European broadcasters.

Ukrainian forces had already received enough equipment from Western allies for their campaign but were waiting for the full complement of armoured vehicles to arrive to reduce their casualties, Zelenskiy said.

In a major step up in Western military support for Ukraine, Britain announced it was sending Storm Shadow cruise missiles that would give Kyiv the ability to strike targets deep behind Russian lines.

“The key here is to give Ukraine that capability. To defend itself,” Defence Secretary Ben Wallace told parliament in London.

Western countries including the United States had previously held back from providing long range weapons for fear of provoking Russian retaliation. Wallace said Britain had weighed the risk.

The war in Ukraine is at a turning point, with Kyiv poised to unleash its new counterstrike after six months of keeping its forces on the defensive, while Russia mounted a huge winter offensive that failed to capture significant territory.

Moscow’s main target for months has been Bakhmut, which it has yet to fully capture despite the bloodiest ground combat in Europe since World War Two.

Yevgeny Prigozhin, head of Russia’s Wagner private army which has led the fight in Bakhmut, has acknowledged Ukrainian gains. Ukrainian operations were “unfortunately, partially successful” he said on Thursday, calling Zelenskiy’s assertion that the counteroffensive had not yet begun “deceptive”.

A once secretive figure, Prigozhin has released messages daily over the past week, often with obscenity-filled tirades, complaining of Russia’s failure to support his forces.

In his latest audio message he said the situation on Bakhmut’s flanks, guarded by regular Russian troops, was unfolding according to the “worst of all expected scenarios” with territory captured over months being “thrown away”.

On Tuesday, Prigozhin said a Russian brigade had fled from the trenches, giving up a swathe of land southwest of Bakhmut. That was backed up by a Ukrainian unit that claimed to have routed the Russian brigade, destroying two of its companies.

The commander of Ukraine’s ground forces said on Wednesday Russian forces had retreated in places by as much as two km. Ukraine has boasted of few similar advances since its last big offensive last November.

Russia’s military has not acknowledged the setbacks. In its regular daily briefing on Thursday, the Defence Ministry said Russian troops were continuing to assault the western part of Bakhmut, with paratroopers pinning down Ukrainian army units on the flanks.

Kremlin spokesman Dmitry Peskov acknowledged that the war was “very difficult”. He said he had no doubt that Bakhmut “will be captured and will be kept under control”.

Reuters could not independently verify the situation on the ground in Bakhmut.