Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

Fierce fighting is ongoing southwest of Lysychansk -- the last city in Ukraine’s Luhansk Oblast that remains under Ukrainian control, Ukraine’s General Staff said. If Lysychansk falls, one of the two Donbas regions would effectively be seized by Russia.

Russian forces have secured positions in the northwestern and southeastern parts of the Lysychansk Oil Refinery and are firing artillery on Ukrainian forces around the refinery and in nearby settlements, Ukraine’s General Staff said.

Serhii Haidai, the head of the Luhansk RMA, said Russian forces are shelling the city from several directions, but there’s no street fighting in Lysychansk and the city is not yet encircled.

-ABC News' Max Uzol and Fidel Pavlenko

President Joe Biden at his press conference in Madrid Thursday announced $800 million more in aid for Ukraine, including air defense systems and offensive weapons.

A reporter asked how to explain to the American people a joint statement from Biden and other G-7 leaders Monday that read: "We will continue to provide financial, humanitarian, military and diplomatic support and stand with Ukraine for as long as it takes."

Asked if that meant indefinite support from the U.S., or whether there would be a time support from the U.S. would stop, Biden replied: "We are going to support Ukraine as long as it takes."

"I don't know what -- how it's going to end," Biden added, "But it will not end with a Russian defeat of Ukraine in Ukraine."

Ukrainian President Volodymyr Zelenskyy said recently that the war needs to end by the winter. But Biden said that, "no," that assessment hadn’t changed his calculation in terms of the pace and kind of assistance the U.S. is sending Ukraine.

Biden was also pressed on record high gas prices that he has attributed to the war in Ukraine. "How long is it fair to expect American drivers and drivers around the world to pay that premium for this war?" he was asked by a reporter.

"As long as it takes," he replied. "Russia cannot, in fact, defeat Ukraine and move beyond Ukraine. This is a critical, critical position for the world."

Biden highlighted his domestic efforts to bring down the price at the pump, like releasing oil from the Strategic Petroleum Reserve, and asking Congress and states to approve a gas tax holiday to help save consumers money at the pump.

"So I think there's a lot of things we can do, and we will do, but the bottom line is ultimately the reason why gas prices are up is because of Russia," he said. "Russia, Russia, Russia. The reason why the food crisis exists is because of Russia. Russia not allowing grain to get out of Ukraine."

-ABC News' Ben Gittleson and Molly Nagle

Almost all soldiers of the Ukrainian Azov Regiment who were released from Russian captivity return home wounded, a representative of the Association of Families of Azovstal Defenders told local media on Wednesday.

"Almost everyone – 99% – were left without arms, without legs. Some do not hear, some do not see, but their eyes are happy,” Tetiana Kharko said.

According to Kharko, the sister of a captured Marine commander, some troops “talk with tears in their eyes, some can't [speak].” The representative added that the soldiers from the latest exchange of prisoners need urgent medical care and an examination.

In his Wednesday evening address, Ukrainian President Volodymyr Zelenskyy said 95 Azovstal defenders returned home from Ukrainian captivity, along with dozens of other troops.

-ABC News' Edward Szekeres, Max Uzol, Natalya Kushnir and Yuriy Zaliznyak

The Russian military committed "a clear war crime" when its forces bombed a packed drama theater in the Ukrainian city of Mariupol in March, Amnesty International said Thursday.

The London-based international human rights group published a new report documenting how the deadly blitz on the Donetsk Academic Regional Drama Theater unfolded, citing interviews with numerous survivors and witnesses as well as "extensive digital evidence," which included photographs, videos, radio intercepts, satellite imagery and radar data. The report concluded that the evidence indicates the attack "was almost certainly an airstrike carried out by the Russian military," with the theater as "the intended target."

"After months of rigorous investigation, analysis of satellite imagery and interviews with dozens of witnesses, we concluded that the strike was a clear war crime committed by Russian forces," Amnesty International Secretary-General Agnes Callamard said in a statement Thursday.