A Russian missile strike killed at least one person in the Ukrainian capital Kyiv in the early hours of Sunday, according to Mayor Vitali Klitschko.

The strike was the first large-scale attack using missiles and drones since the U.S. said it had negotiated two ceasefire accords with Russia and Ukraine.

While Russian missile and drone bombardments have been unrelenting over more than three years of war, they have intensified in recent weeks amid U.S.-led peace talks.