Russia launched a massive overnight assault on Kyiv, killing at least 15 people, including four children, and injuring 38 others, Ukrainian officials said early Thursday.

The combined strikes, which Ukraine’s air force said involved 629 drones and missiles, marked one of the heaviest attacks on the capital since the war began. More than 20 locations across the city were hit, damaging homes and knocking out power for about 60,000 residents.

Ukrainian President Volodymyr Zelenskyy condemned the assault, saying Russia had chosen “ballistics over the negotiating table.” He renewed his call for “new tough sanctions” against Moscow, warning that missed diplomatic opportunities had allowed the war to escalate further.

Among the dead was a 2-year-old child, according to Tymur Tkachenko, head of Kyiv’s city administration. Ten other minors were among the injured. Explosions were also reported near central Kyiv, a rare occurrence since the early months of the invasion.

Russia’s Defense Ministry claimed the strikes targeted Ukraine’s military air bases and defense industry, using long-range weapons including Kinzhal missiles. “All designated objects were hit,” the ministry said in a statement.

Collateral damage extended to international institutions, with the European Union delegation and British Council offices in Kyiv sustaining damage. EU President Ursula von der Leyen confirmed no staff were harmed.

The assault came as U.S.-backed efforts to push Moscow and Kyiv toward negotiations faced new obstacles. President Donald Trump had recently stepped up calls for a settlement, but talks have stalled amid Russia’s intensifying attacks.

Meanwhile, Ukraine has escalated strikes on Russian oil infrastructure, causing fuel shortages in some regions. Russia claimed to have intercepted 102 Ukrainian drones overnight, including in Samara, where a refinery was set ablaze.

Despite the spiraling hostilities, Kremlin spokesperson Dmitry Peskov insisted Thursday that Moscow “maintains its interest in continuing the negotiation process,” even as strikes on Ukraine continue.

The attack follows a July bombardment of Kyiv that killed 31 people, the deadliest strike on the capital this year. Fighting has also spread to Dnipropetrovsk region, where Ukrainian forces say they repelled Russian troops near two villages.

Senior Ukrainian officials are expected to meet counterparts in New York on Friday to discuss security guarantees from allies. In a related move, Zelenskyy appointed former deputy prime minister Olha Stefanishyna as Ukraine’s new ambassador to the United States.