Residents sobbed outside the burnt-out apartment block and smoke billowed after the early-morning attack in Kryvyi Rih, a half-hour drive from the huge reservoir emptied last week by the destruction of a dam that flooded a swathe of southern Ukraine.

Officials said at least 25 people were wounded and others could still be trapped under the rubble of the five-storey apartment block hit early in the morning.

Survivors described two explosions. Olha Chernousova said she was thrown out of her bed by a violent blast wave. She escaped onto her balcony to wait for rescuers. "I thought I would have to jump into a tree."

The street and courtyard were strewn with glass and bricks. At least five cars were ruined husks.

"Russian killers continue their war against residential buildings, ordinary cities and people," Zelenskiy said on Telegram. The Ukrainian president was born in the city.

Moscow denies intentionally targeting civilians. It has stepped up missile and drone attacks on Ukrainian cities in recent weeks as Kyiv unleashed a long-awaited counteroffensive to recapture territory held by Russian troops.

After seven months of a huge Russian offensive that yielded scant gains despite the bloodiest ground combat in Europe since World War Two, Ukraine began its assault last week.

So far the offensive is still in its early days, with tens of thousands of fresh Ukrainian troops and hundreds of Western armoured vehicles yet to be committed to the fight.

Confirmed video footage from villages over the past two days show that Ukraine has already captured more ground than at any time since November.

But it has yet to pierce Russia's main defensive lines, which Moscow has had months to prepare.

Russia has also accused Ukraine of cross-border shelling as Kyiv carries out counteroffensive operations. The governor of Kursk in Russia said on Tuesday several houses had been damaged and power supplies disrupted in two villages in the region near the border. Ukraine does not comment on reports of incidents in Russia.

During the early hours of Tuesday, air raid sirens blared across the whole of Ukraine, with Kyiv's military officials saying air defence forces destroyed all Russian missiles targeting the capital.

Ukraine's top military command said that air forces destroyed 10 out of 14 cruise missiles Russia launched on Ukraine and one of four Iranian-made drones.

After a week of giving little or no information about its offensive, Ukraine said on Monday it had recaptured seven settlements so far. Troops have advanced up to 6.5 km (four miles) and seized 90 square km of ground along a 100 km-long stretch of the southern front line, Deputy Defence Minister Hanna Maliar said.

Russia has not acknowledged any Ukrainian gains and says its forces have repelled advances since June 4.

Russia's Defence Ministry released video footage on Tuesday of what it said were German-made Leopard tanks and U.S.-made Bradley Fighting Vehicles captured by Russian forces in a battle with Ukrainian forces.

Reuters could not immediately verify the location or timing of the footage.

Military analysts say the fighting so far is probably still probing attacks by the Ukrainians who have yet to unleash the bulk of their forces, while Russia's main defensive fortifications still lie further back.

Last week's destruction of the Nova Kakhovka dam created a humanitarian disaster across both sides of the front line in the war zone and could damage agriculture in one of the world's breadbaskets for decades.

Both sides have accused each other of sabotaging it. Western countries say Ukraine would have had no reason to inflict such a catastrophe on itself, especially just as its forces were taking the offensive.