Ukraine said it struck a Russian air base on Saturday, while Russia continued to attack Ukraine with hundreds of drones overnight as part of a stepped-up bombing campaign that has dashed hopes for a breakthrough in efforts to end the more than 3-year-old war.

Hundreds of flights were delayed or canceled due to Ukrainian drone strikes on Saturday and overnight, according to Russia’s Transport Ministry.

The district's administrative centre, the town of Sergiyev Posad, is considered the religious centre of the Moscow Region and a spiritual heart of Russia's Orthodox Church. The city's monastery, the Trinity Lavra of St. Sergius that was founded in the 14th century, is a UNESCO World Heritage site.