Russia pounded Ukraine’s Black Sea city of Odesa late on Thursday with one of its biggest drone attacks, injuring three teenagers and sparking fires as the Czech president visited, Ukrainian officials said.

The attack comes as the United States is pushing for a peace deal between Ukraine and Russia, and hoping to agree a partial ceasefire that would halt strikes on energy infrastructure by both sides.

Czech President Petr Pavel, a vocal backer of Kyiv who has led an effort to source more than one million artillery shells for Ukraine’s war effort, was in the port city for talks with regional officials at the time of the strikes.

“Significantly, it was during our meeting that the enemy once again massively attacked the Odesa region,” Governor Oleh Kiper said on the Telegram messaging app.

The long-range drones buzzed into the city in several waves, damaging infrastructure, residential houses and commercial buildings, and causing multiple fires, the interior ministry said.

Around 25 cars had been set ablaze at a car repair shop.

“We could not do anything. We were just standing and watching as everything was on fire. I am in total shock,” the shop’s owner, who gave her name as Inna, told Reuters.

Oleksandr Kovalenko, a military analyst, told Reuters that Russia used new tactics for the attack, having its drones descend from a higher altitude than usual and at high speeds to make it harder for Ukraine’s air defences.

He said it was one of the “most massive” attacks on Odesa since Russia invaded in February 2022: “It was intimidation. Terror against the civilian population.”

Separately on Friday, Russia and Ukraine accused each other of attacking a major Russian gas pumping and measuring station that lies in a part of Russia’s Kursk region that Moscow’s forces recaptured from Ukraine earlier this month.

Moscow said Ukraine had blown up the facility in an act of terrorism. Kyiv said Russian forces shelled it with artillery in “a provocation” and denied any involvement.

Both Russia and Ukraine have agreed during separate talks with U.S. officials that they are ready for a moratorium on strikes on energy infrastructure. Moscow rejected a more comprehensive 30-day ceasefire.

Ukrainian, U.S. and Russian delegations are due to meet in Saudi Arabia separately on Monday to discuss the details, officials have said.

Russia launched a total of 214 drones at Ukraine overnight, the air force said. It did not specify how many drones targeted Odesa. The air force said it shot down 114 of the drones and that another 81 drones were “lost”, its term for those suppressed using electronic warfare defences.

Ukraine has used drones to continue striking targets in Russia, hitting oil infrastructure and a strategic bomber base in recent days.