KYIV, Ukraine (AP) — Heavy fighting was raging in Ukraine’s eastern Donbas region, where Russian forces have stepped up their bombardments beyond the frontlines, Britain’s Defense Ministry said Tuesday.

Moscow faces stiff Ukrainian resistance to its effort to encircle the area around the city of Sievierodonetsk and consolidate Russian control of the Luhansk region — the main focus but not the only Russian effort in the campaign to capture the Donbas, the ministry said in the update posted on Twitter.

Cities not under Russian control were constantly shelled, and one Ukrainian official said Russian forces targeted civilians trying to flee.

Russia is bent on capturing the eastern industrial heartland of coal mines and factories and has made some localized gains, the ministry said in its daily intelligence briefing, but Ukraine’s long-established Joint Force Operation likely retains effective command and control of that front.

To the north in Ukraine’s second-largest city, Kharkiv, residents lined up for rations of tea, sugar, pasta and cereal, holding out plastic bags to receive cups of flour and other supplies. An aid worker said many had fled the city while it was under siege and returned, lacking a regular income and the means to feed their families without help.

Kherson, a region bordering Donetsk to the east and Crimea to the south, was taken by Russian forces early in the war. An official there said the region’s pro-Kremlin administration will ask Moscow to set up a military base there.

“We will be asking for it, the entire population is interested in it. It is vitally important and will become a security guarantee for the region and its residents,” said Kirill Stremousov, deputy head of the Russia-installed administration in Kherson.

Ukrainian officials have speculated Russia plans to stage a referendum in the region to declare its independence, similar to ones held in Donetsk and Luhansk regions in 2014. Moscow recognized the self-proclaimed Donetsk and Luhansk republics two days before invading Ukraine, using that as a pretext to send troops to its ex-Soviet neighbor.

Stremousov denied such plans earlier this month and said the region will ask the Kremlin to make it part of Russia instead. Kremlin spokesman Dmitry Peskov has said it is up to the people of Kherson to decide how and where they want to live.

Meeting in Tokyo with fellow leaders in the Indo-Pacific security coalition known as the Quad, President Joe Biden said Tuesday that Russia’s war in Ukraine had brought a “dark hour in our shared history.”

Global defense leaders on Monday agreed to send more advanced weapons to Ukraine, including a Harpoon launcher and missiles to protect its coast, Defense Secretary Lloyd Austin told reporters.

Ukrainian President Volodymyr Zelenskyy called for “maximum” sanctions against Russia, with an embargo on Russian oil, a complete cutoff of trade and withdrawal of foreign companies, in a video address to the World Economic Forum in Davos, Switzerland.

Later, in his evening address to the nation, Zelenskyy said four missiles had killed 87 people last week in the town of Desna, 34 miles north of Kyiv, in one of the deadliest single strikes in the war.

Also Monday, a Ukrainian court sentenced a captured Russian soldier, Sgt. Vadim Shishimarin, 21, to the maximum penalty of life in prison for killing a civilian. He was sentenced for shooting a 62-year-old man in the head in a village in the northeastern Sumy region in the opening days of the war. His attorney indicated he may appeal.

Mary Ellen O’Connell, an expert on international law at the University of Notre Dame, said putting Shishimarin on trial could prove “extremely detrimental to Ukrainian soldiers in the hands of Russia.” Russia may decide to hold “show trials” of Ukrainians to boost the morale of its own soldiers and spread disinformation, she said.

Russian authorities have threatened to hold trials of some captured Ukrainians — namely, fighters who held out at Mariupol’s shattered steel plant, the last stronghold of resistance in the strategic southern port city. They surrendered and were taken prisoner last week, at which point Moscow claimed the capture of Mariupol was complete.

Ukrainian prosecutors are investigating thousands of potential war crimes. Russian forces in Mariupol bombed a theater where civilians were sheltering and struck a maternity hospital. In the wake of Moscow’s withdrawal from around Kyiv weeks ago, mass graves were discovered and streets were strewn with bodies in towns such as Bucha.

Russian authorities have seized upon the far-right origins of one of the regiments there, calling the Azov Regiment’s fighters “Nazis” and the country’s top prosecutor has asked Moscow’s Supreme Court to designate the regiment as a terrorist organization. Russia’s main investigative body said it intends to interrogate the Mariupol defenders to “identify the nationalists” and determine whether they were involved in crimes against civilians.

Family members of the Ukrainian fighters have pleaded for their eventual return to Ukraine as part of a prisoner swap.

In a rare public expression of opposition to the war from Russia’s elite, veteran diplomat Boris Bondarev quit his post at the U.N. office at Geneva and sent a letter denouncing the war and saying he had never been so ashamed of his country.

Bondarev told The Associated Press: “It is intolerable what my government is doing now.”