Ukrainian President Volodymyr Zelenskyy accused the West of lacking courage as his country fights to stave off Russia’s invasion, making an exasperated plea for fighter jets and tanks to sustain a defense in a conflict that has ground into a war of attrition.

Speaking after U.S. President Joe Biden met with senior Ukrainian officials in Poland on Saturday, Zelenskyy lashed out at the West’s “ping-pong about who and how should hand over jets and other defensive weapons to us” while Russian missile attacks kill and trap civilians.

“I’ve talked to the defenders of Mariupol today. I’m in constant contact with them. Their determination, heroism and firmness are astonishing,” Zelenskyy said in a video address early Sunday, referring to the besieged southern city that has suffered some of the war’s greatest deprivations and horrors. “If only those who have been thinking for 31 days on how to hand over dozens of jets and tanks had 1% of their courage.”

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Russia’s invasion of Ukraine, now in its 32nd day, has stalled in many areas, its aim to quickly encircle the capital, Kyiv, and force its surrender faltering in the face of staunch Ukrainian resistance — bolstered by weapons from the U.S. and other Western allies.

However, Western military aid has, so far, not included fighter jets. A proposal to transfer Polish planes to Ukraine via the United States was scrapped amid NATO concerns about getting drawn into a military conflict with Russia.

“So, who is in charge of the Euro-Atlantic community? Is it still Moscow, thanks to its scare tactics?” Zelenskyy exclaimed as he delivered his pointed remarks. “Our partners must step up their aid to Ukraine.”

Britain’s defense ministry said Sunday that the battlefield across northern Ukraine remains largely static as local Ukrainian counterattacks hamper Russian attempts to reorganize their forces. It said Russia’s forces looked to be trying to encircle Ukrainian forces directly facing the separatist regions in the country’s east.

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Moscow has claimed that its focus is on wresting the entirety of Ukraine’s eastern Donbas region from Ukrainian control. The region has been partially controlled by Russia-backed separatists since 2014. A high-ranking Russian military official said Friday that troops were being redirected to the east from other parts of the country.

Despite those assertions, Russian rockets struck the western city of Lviv on Saturday while Biden visited neighboring Poland, serving as a reminder that Moscow is willing to strike anywhere in Ukraine.

Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said Sunday that it used air-launched cruise missiles to hit a fuel depot and a defense plant in Lyiv. Konashenkov said another strike with sea-launched missiles destroyed a depot with air defense missiles in Plesetske just west of Ukraine’s capital, Kyiv.

The strikes came as Biden wrapped up a visit to Poland, where he met Ukraine’s foreign and defense ministers, visited U.S. troops and saw refugees from the war. Before leaving, he delivered a forceful and highly personal condemnation of Russia President Vladimir Putin, saying: “For God’s sake, this man cannot remain in power.”

The White House quickly clarified that Biden wasn’t calling for an immediate change in government in Moscow. Kremlin spokesman Dmitry Peskov denounced the remark, saying “It’s not up to the president of the U.S. and not up to the Americans to decide who will remain in power in Russia.”

Early Sunday, a chemical smell still lingered in the air as firefighters in Lviv, about 45 miles (72 kilometers) from the Polish border, sprayed water on a burned section of an oil facility hit in the Russian attack.

A security guard at the site, Yaroslav Prokopiv, said he saw three rockets strike and destroy two oil tanks but no one was hurt.

“The third strike threw me to the ground,” he said.

Russia’s back-to-back airstrikes shook the city that has become a haven for an estimated 200,000 people who have fled bombarded towns and cities. Lviv also has been a way-station for most of the 3.8 million refugees have left Ukraine since Russia first invaded on Feb. 24.

The city had been largely spared since the invasion began, although missiles struck an aircraft repair facility near the main airport a week ago.

In the dim, crowded bomb shelter under an apartment block a short way from the first blast site, Olana Ukrainets, a 34-year-old IT professional, said she couldn’t believe she had to hide again after fleeing from the northeastern city of Kharkiv, one of the most bombarded cities of the war.

“We were on one side of the street and saw it on the other side,” she said. “We saw fire. I said to my friend, ‘What’s this?’ Then we heard the sound of an explosion and glass breaking. We tried to hide between buildings. I don’t know what the target was.”

In his video address, Zelenskyy angrily warned Moscow that it was sowing a deep hatred for Russia among the Ukrainian people, as constant artillery barrages and aerial bombings are reducing cities to rubble, killing civilians and driving others into shelters, leaving them to scrounge for food and water to survive.

“You are doing everything so that our people themselves leave the Russian language, because the Russian language will now be associated only with you, with your explosions and murders, your crimes,” Zelenskyy said.

A nuclear research facility in Kharkiv, which is Ukraine’s second-largest city and located near the Russian border, again came under fire Saturday. Ukraine’s nuclear watchdog said that because of ongoing hostilities it was impossible to assess the extent of the damage.

Kharkiv has been besieged by Russian forces since the start of the invasion and has come under repeated shelling that has hit residential buildings and critical infrastructure.

Ukrainian authorities have previously reported that Russian shelling had damaged buildings at the facility, but there had been no release of radiation. The International Atomic Energy Agency has said the nuclear material in the facility is always subcritical and the inventory of radioactive material is very low, reducing the risks of radiation release.

Along with the 3.8 million people who have fled Ukraine entirely, the invasion has driven more than 10 million people from their homes, almost a quarter of Ukraine’s population. Thousands of civilians are believed to have been killed.