Russia and Ukraine engaged in large-scale dueling air assaults overnight Saturday, launching hundreds of drones in hourslong raids. The attacks came as both sides were carrying out the war’s largest prisoner exchange — a stark reminder that despite ongoing efforts to de-escalate the conflict, a resolution remains far off.

Russia’s attack on Ukraine was particularly significant, involving 250 long-range drones and 14 ballistic missiles, with Kyiv, the Ukrainian capital, the main target. Ukraine’s air force said it intercepted six missiles and nearly all the drones, but at least 15 people in Kyiv were injured as drones and debris from intercepted weapons crashed into apartments, setting them ablaze.

Kyiv residents were jolted awake by the booms of the city’s antiaircraft batteries trying to down incoming missiles and drones. The night sky lit up with bright streaks from climbing air defense missiles and red tracer trails from heavy machine guns. Explosions set off car alarms, adding to the cacophony of gunfire and the buzz of attack drones.

“It was a difficult night for all of Ukraine,” President Volodymyr Zelensky said in a statement Saturday morning. “With each such attack, the world becomes more certain that the cause of prolonging the war lies in Moscow,” he added, noting that Russia had repeatedly ignored Ukraine’s offers to enforce a temporary cease-fire.

Still, Ukraine has also escalated its air assaults on Russia in recent weeks. Earlier this week, it fired hundreds of drones at Russian cities, with Moscow a prime target, in one of the largest barrages of the war, forcing some airports to temporarily close.