At least 15 people were killed and two dozen more are feared trapped after Russian Uragan rockets hit a five-storey apartment block in Ukraine’s Donetsk region, local officials said on Sunday as rescuers picked their way through rubble.

Ukraine also reported clashes with Russian troops on fronts in the east and south, while Moscow said its forces struck Ukrainian army hangars storing US-produced M777 howitzers, a type of artillery, near Kostyantynivka in Donetsk region.

Donetsk Governor Pavlo Kyrylenko said the strike on the apartment building took place on Saturday evening in the town of Chasiv Yar.

The regional emergency service gave the death toll at 15 on Sunday afternoon, adding that 24 more people could still be under the rubble.

“We ran to the basement, there were three hits, the first somewhere in the kitchen,” said a local resident who gave her name as Ludmila, speaking as rescuers removed a body in a white sheet and cleared rubble using a crane as well as their hands.

“The second (strike), I do not even remember, there was lightning, we ran towards the second entrance and then straight into the basement. We sat there all night until this morning.”

Andriy Yermak, chief of staff to President Volodymyr Zelenskiy, said in a Telegram post that the strike was “another terrorist attack,” and that Russia should be designated as a state sponsor of terrorism as a result.

Russia, which says it is conducting a “special military operation” to demilitarise Ukraine, denies deliberately attacking civilians.

Luhansk and Donetsk provinces comprise the Donbas, Ukraine’s eastern industrial region that has become Europe’s biggest battlefield for generations.

Russia wants to wrest control of the Donbas on behalf of the separatists that it supports.

Moscow says ejecting the Ukrainian military out of the region is central to what it calls its “special military operation” to ensure its own security, an offensive that has lasted for more than four months and which the West calls an unprovoked war.

American howitzers

Russian forces attacked Ukrainian positions near the town of Sloviansk in Donetsk but were forced to withdraw, Ukraine’s military said, adding that Russian forces had launched a cruise missile attack on the northeastern city of Kharkiv from their side of the border. It gave no details of damage or casualties.

Luhansk region Governor Serhiy Gaidai said Russian forces were gathering in the area of the village of Bilohorivka, about 50 km (30 miles) east of Sloviansk.

“The enemy is ... shelling the surrounding settlements, carrying out air strikes, but it is still unable to quickly occupy the entire Luhansk region,” he said on Telegram.

Russia claimed control over all of Luhansk province last weekend. Russia’s defence ministry said its forces had destroyed two hangars near the Donetsk town of Kostyantynivka holding the US-made M777 howitzers, which it said had been used to shell residential areas of Donetsk.

Reuters could not independently verify battlefield accounts.

Ukrainian military spokespeople were not immediately available for comment.

Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw.

In the south, Ukrainian forces fired missiles and artillery at Russian positions including ammunition depots in the Chornobaivka area, Ukraine’s military command said.

Lavrov walks out

US Secretary of State Antony Blinken, on a trip to Asia, urged the international community to join forces to condemn Russian aggression. He said he had raised concerns with his Chinese counterpart, Wang Yi, over Beijing’s alignment with Moscow.

The two met for more than five hours on the sidelines of a gathering of G20 foreign ministers on the Indonesian island of Bali. Russia’s Sergei Lavrov walked out of a meeting there on Friday, denouncing the West for “frenzied criticism”.

Shortly before the Russian invasion, Beijing and Moscow announced a “no limits” partnership, although US officials have said they have not seen China evade U.S.-led sanctions on Russia or provide it with military equipment.

Zelenskiy dismissed several of Ukraine’s senior envoys abroad on Saturday, saying it was part of “normal diplomatic practice”. He said he would appoint new ambassadors to Germany, India, the Czech Republic, Norway and Hungary.

Zelenskiy has urged his diplomats to drum up international support and high-end weapons to slow Russia’s advance.

Ukraine suffered a diplomatic setback on Saturday, when Canada said it would return a repaired turbine that Russia’s state-controlled Gazprom used to supply natural gas to Germany. Ukraine had argued that a return would violate sanctions on Russia.