KYIV, Ukraine — Russia fired more than 100 drones at civilian areas of Ukraine overnight, authorities said Monday, as the Kremlin dismissed the country’s transport chief after a weekend of travel chaos when Russian airports grounded hundreds of flights due to the threat of Ukrainian drone attacks.

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.