Ukraine started evacuating residents from the northeastern city of Sumy on Tuesday through a humanitarian corridor as agreed with Russia, Ukraine's UNIAN news agency reported.

"The first column started moving out of the city at 10:00 (0800 GMT)," the agency said.

Dmytro Lunin, acting head of the military-civilian administration of Poltava City in northeast Ukraine, said that 35 buses were sent to Sumy for the evacuation.

"The convoy includes representatives of the Red Cross and doctors. We also sent 20 tons of humanitarian aid: food and medicine," he said, noting that the Ukrainian side observes a ceasefire to ensure the safety of civilians during the evacuation.