At least four people were killed overnight and on Saturday morning as Russia continued to pound Ukraine with hundreds of drones and cruise missiles as part of a stepped-up bombing campaign that has further dampened hopes for a breakthrough in efforts to end the more than three-year-old war.

Russia fired 597 drones and decoys, along with 26 cruise missiles, into Ukraine overnight into Saturday, Ukraine's air force said.

As Russia intensifies its air strikes against Ukraine, its tactics have visibly shifted, with a growing number of missile and drone attacks now targeting western regions once considered relatively safe.