Russian forces have bombarded eastern Ukraine from land and air, killing at least 13 civilians, Ukraine's military said Friday, while President Volodymyr Zelenskyy said the Donbass region was "completely destroyed" and called it "hell."

As the war neared the three-month mark, the Russians were intensifying their efforts to subdue the Donbass region, the Ukrainian general staff said.

They had hit civilian infrastructure with "massive" artillery shelling, including multiple rocket launchers, the general staff said in a statement. Russian aircraft had also struck at targets.

In fighting in the eastern Donbass region, 13 people were killed and 60 houses destroyed when Russia shelled the neighboring cities of Severodonetsk and Lysychansk, northwest of Luhansk, regional Governor Serhiy Haidai said in a Telegram post Friday.

"The Donbass is completely destroyed," President Zelenskyy said in an address on Thursday night. "It is hell there – and that is not an exaggeration."

There were also constant strikes on the Odessa region in the south, he said.

Reuters could not independently verify the reports and Russia denies targeting civilians.

Russia's focus on Donbass follows its failure to capture the capital Kyiv in the early stages of the invasion launched by Russian President Vladimir Putin on Feb. 24.

Thousands of people – many of them civilians – have been killed and whole towns and cities razed in the gravest crisis in Europe in decades.

Almost a third of Ukraine's people have fled their homes, including more than 6 million who have left the country in a refugee exodus, while others remain trapped in cities pulverized by Russian bombardments.

British military intelligence said on Friday that Russia is likely to further reinforce its operations in Donbass once it finally secures the southern port city of Mariupol – the scene of a weekslong siege and Russia's most significant success in an otherwise faltering campaign.

The region, an industrial powerhouse, compromises the Donetsk and Luhansk areas, which Moscow claims on behalf of separatists.

Putin calls the invasion of Ukraine a "special military operation" to rid the country of fascists – an assertion Kyiv and its Western allies say is a baseless pretext for an unprovoked war.

The Kremlin leader was due to hold a security council meeting later on Friday.

Mariupol steel mill

The commander of Ukraine's Azov Regiment said in a video statement published Friday that civilians and heavily wounded Ukrainian fighters had been evacuated from the Azovstal steelworks in the devastated city of Mariupol.

"We have constantly emphasized the three most important conditions for us: civilians, wounded and dead," Denys Prokopenko, the commander, said in the video shared by the Azov Regiment on the Telegram messaging service.

"The civilians have been evacuated. The heavily wounded received the necessary assistance and they were evacuated, to be later exchanged and delivered to territory controlled by Ukraine," Prokopenko said.

Prokopenko said the process of removing the dead from the Azovstal plant, the last bastion of Ukrainian resistance against Russian forces in Mariupol, was still underway. "I hope that in the near future, relatives and Ukraine will be able to bury their soldiers with honor," he said.

With the number of defenders left holed up in a Mariupol steel factory dwindling, Russian commanders will be coming under increasing pressure to reallocate troops from the strategic southern port city to bolster their offensive in eastern Ukraine, Britain’s Defense Ministry said Friday.

More than 1,700 defenders of the Azovstal steel plant in Mariupol have surrendered since Monday, Russian authorities said, in what appeared to be the final stage in the nearly three-month siege of the now-pulverized port city.

Meanwhile, Western powers, who have strongly condemned Russia's actions and sought to isolate Moscow with an array of sanctions, were stepping up their support for Ukraine. The U.S. Senate approved nearly $40 billion in new aid for Ukraine, by far the largest U.S. aid package to date. The White House is also working to put advanced anti-ship missiles in the hands of Ukrainian fighters to help defeat Russia's naval blockade, which has largely stopped Ukraine's exports of food.

U.S. Secretary of State Antony Blinken accused Russia of using food as a weapon by holding "hostage" supplies for not just Ukrainians, but also millions around the world. The war has caused global prices for grains, cooking oils, fuel and fertilizer to soar.

The EU said it is looking into ways of using the frozen assets of Russian oligarchs to fund the reconstruction of Ukraine, while the United States has not ruled out possibly placing sanctions on countries that purchase Russian oil.

Hold out

The past week has seen Russia secure its biggest victory since the invasion began, with the Kyiv government ordering the defenders of a steelworks in Mariupol to stand down after a protracted siege.

British military intelligence said as many as 1,700 soldiers were likely to have surrendered at the Azovstal steel factory, matching a similar number released on Thursday by Moscow.

Ukrainian officials, who have tried to arrange a prisoner swap, have declined to comment on the number, saying it could endanger rescue efforts.

Late on Thursday, Sviatoslav Palamar, deputy head of the Azov Regiment defending the steelworks, released an 18-second video in which he said he and other commanders were still inside the plant.

"A certain operation is going on, the details of which I will not disclose," he said.

The International Committee of the Red Cross said it had registered hundreds of prisoners from Azovstal now held by Russia, but it has not given a precise number.

The leader of Russian-backed separatists in control of the area said nearly half of the fighters remained inside the steelworks. The wounded were given medical treatment while those who were fit were taken to a penal colony and were being treated well, he said.