U.S. President Donald Trump and Ukrainian President Volodymyr Zelenskiy agreed on Wednesday to work together to end Russia’s war with Ukraine, in what the White House described as a “fantastic” one-hour phone call.

In their first conversation since an Oval Office shouting match on February 28, Zelenskiy thanked Trump for U.S. support and the two leaders agreed that technical teams would meet in Saudi Arabia in the coming days.

Zelenskiy asked Trump for more air defence support to protect his country against Russian attacks and the U.S. president said he would help locate the necessary military equipment in Europe, the White House said.

Trump briefed Zelenskiy on his phone call on Tuesday with Vladimir Putin, in which the Russian president rejected a proposed full 30-day ceasefire sought by Trump that Ukraine said it would be prepared to accept, but agreed to pause attacks on energy infrastructure.

That narrowly defined pause appeared in doubt on Wednesday, however, with Moscow saying Ukraine hit an oil depot in southern Russia while Kyiv said Russia had struck hospitals and homes, and knocked out power to some railways.

Still, the two sides carried out a prisoner exchange, each releasing 175 troops in a deal facilitated by the United Arab Emirates. Moscow said it freed an additional 22 wounded Ukrainians as a goodwill gesture.

Zelenskiy, describing his conversation with Trump as “positive, very substantive and frank,” said he had confirmed Kyiv’s readiness to halt strikes on Russian infrastructure and to accept an unconditional frontline ceasefire as the U.S. proposed earlier.

“One of the first steps toward fully ending the war could be ending strikes on energy and other civilian infrastructure. I supported this step, and Ukraine confirmed that we are ready to implement it,” he said on social media.

Later, the Ukrainian president told reporters in a video call that Trump understands Kyiv will not recognize occupied land as Russian.

Zelenskiy said the Russian strikes, which he said were carried out since Trump’s call with Putin, showed that Russia was not ready for peace. He said the U.S. should be in charge of monitoring any ceasefire, adding a halt to infrastructure attacks could be quickly established.

The Kremlin said it had called off planned attacks on Ukraine’s energy infrastructure, including by shooting down seven of Russia’s own drones heading towards Ukraine. It accused Kyiv of failing to call off its own attacks in what it called an attempt to sabotage the agreement.

Trump suggested to Zelenskiy the U.S. could help run, and possibly own, Ukraine’s nuclear power plants, according to a statement by the U.S. administration. Europe’s largest nuclear power plant, in Ukraine’s Zaporizhzhia region, has been shut down since Russian troops occupied it in 2022.

Zelenskiy said Ukraine has begun talks with the U.S. about its possible involvement in restoring the Zaporizhzhia plant.

Trump has long promised to end Europe’s deadliest conflict since World War Two. But his outreach to Putin has unnerved European allies, who fear it heralds a fundamental shift after 80 years in which defending Europe from Russian expansionism was the core mission of U.S. foreign policy.

Some European leaders said Putin’s rejection of Trump’s proposed full truce was proof Moscow was not seeking peace. The offer to temporarily stop attacking Ukrainian energy facilities counted for “nothing” and Trump would have to win greater concessions, Germany’s defence minister said.

“Putin is playing a game here and I’m sure that the American president won’t be able to sit and watch for much longer,” Boris Pistorius told German broadcaster ZDF.

The EU’s foreign policy chief Kaja Kallas said she would present a proposal to European leaders in Brussels on Thursday to provide Ukraine with 2 million rounds of large-calibre artillery ammunition, according to a letter seen by Reuters.

For most of the past three years, Russia has relentlessly attacked Ukraine’s power grid, arguing that civilian infrastructure is a legitimate target because it facilitates Kyiv’s fighting capabilities. Ukrainians say such attacks have subsided in recent months.

Kyiv has steadily developed capabilities to mount long-range attacks into Russia, frequently using drones to target distant oil and gas sites, which it says provide fuel for Russia’s troops and income to fund the war.

In the attacks overnight, Ukrainian regional authorities said Russian drones damaged two hospitals in the northeastern Sumy region, causing no injuries but forcing the evacuation of patients and staff.

Near Kyiv, a 60-year-old man was injured and airstrikes hit homes and businesses in the Bucha district north of the capital. Attacks damaged power systems for railways in Dnipropetrovsk in the south on Wednesday, the state railway said.

Authorities in the southern Russian region of Krasnodar said a Ukrainian drone attack caused a fire at an oil depot near the village of Kavkazskaya. No one was injured.

The depot is a rail terminal for Russian oil supplies to a pipeline linking Kazakhstan to the Black Sea. A representative of the Caspian Pipeline Consortium operator said oil flows were stable. Two industry sources said the attack could reduce Russian supplies to the pipeline.