KYIV, Ukraine — Ukraine attacked an airfield deep inside Russian territory overnight, officials said Thursday, as the two sides traded strikes amid efforts by the Trump administration to hammer out details of a partial ceasefire.

The attack on the Russian airfield came hours after President Volodymyr Zelenskyy of Ukraine spoke to President Donald Trump and accepted the Kremlin’s offer to mutually pause attacks on energy targets for 30 days as a step toward a broader ceasefire.

Russia’s Defense Ministry said that it had shot down 54 Ukrainian drones in the Saratov region overnight. The region is home to the Engels airfield, which hosts some of Russia’s long-range, nuclear-capable bombers.

While the ministry did not say how many drones had evaded air defenses, The New York Times confirmed that at least one strike targeted the airfield in Engels shortly after sunrise Thursday.

Videos and photographs shared by witnesses on social media and verified by the Times showed an explosion and a large plume of dark smoke rising from the base, and loud secondary explosions.

— The New York Times