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

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.

Russian President Vladimir Putin still wants to seize most of Ukraine, and the outlook for the war remains grim, Avril Haines, the top U.S. intelligence officer, said Wednesday as reported by Reuters.

“In short, the picture remains pretty grim and Russia's attitude toward the West is hardening," Haines said at a Commerce Department conference.

The intelligence officer added that U.S. spy agencies expect the war to grind on “for an extended period of time.” But the Russian forces are so degraded by combat, Haines said, that they likely can only achieve incremental gains in the near term.

Haines also said it will take years for Russia to rebuild its forces. Still, U.S. intelligence agencies foresee three possible scenarios in the war, according to Haines, the most likely being a grinding conflict in which Russian forces "make incremental gains, with no breakthrough."

The other scenarios include a major Russian breakthrough and Ukraine succeeding in stabilizing the frontlines while achieving small gains, perhaps near the Russian-held city of Kherson and other areas of southern Ukraine.

Ukraine is likely to rely on more NATO support as the conflict drags on, with Ihor Zhovkva, the Deputy Head of the Ukrainian Presidential Office, stating Wednesday that Ukraine believes it already meets NATO standards and maintains a course to continue integration.

"No one removes Ukraine's Euro-Atlantic integration from the agenda," Zhovkva said at the NATO summit in Madrid.

Zhovka, who headed the Ukrainian delegation in Madrid, said he was satisfied with the results of the summit. The official also stressed that Ukraine maintains its course to join NATO.

Russia warned Tuesday that Ukraine joining NATO could lead to World War III should Kyiv then attempt to encroach on the Moscow-annexed Crimean Peninsula.

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