The International Committee of the Red Cross (ICRC) says three of its workers have been killed, and two others injured in a strike in eastern Ukraine.

The ICRC did not identify who was behind the attack but called it "unconscionable" that "shelling would hit an aid distribution site".

Earlier, Ukraine's President Volodymyr Zelensky blamed Russia for the shelling, calling it "another Russian war crime".

The agency said its team was preparing to distribute wood and coal briquettes in Viroliubivka village, north of Donetsk city.

"I condemn attacks on Red Cross personnel in the strongest terms," said the agency's president Mirjana Spoljaric, adding that: "Our hearts are broken today as we mourn the loss of our colleagues and care for the injured."

The ICRC said that its vehicles are clearly marked and operate regularly in the frontline region of Donetsk.

Earlier, Ukrainian officials had reported shelling in the village of Viroliubivka and said that workers had been unloading supplies when the attack happened.

In a post on social media, Ukraine's leader blamed a Russian strike. He shared a photo of a white truck in flames branded with the Red Cross logo on its side.

"Today, the occupier attacked the vehicles of the International Committee of the Red Cross humanitarian mission," Zelensky said.

The UN in February this year warned that attacks on aid and humanitarian workers appeared to have increased.

Its humanitarian mission to Ukraine said 50 workers were killed or injured in Ukraine in 2023, including 11 killed in the line of duty, reported AFP news agency.