The International Committee of the Red Cross (ICRC) said it could not distribute humanitarian aid in the East Ukrainian city of Lugansk because of shelling.
"This morning we sent aid trucks to Lugansk but shelling forced them to turn back at Staniza Luganska," the ICRC said on Saturday, ITAR-TASS reported.
It said ten trucks carrying food and medical supplies had left Severodonetsk in the morning but had had to return because of the shelling.
"Aid much needed in East Ukraine. We must be allowed to deliver it in safety, as soon as possible," the independent aid agency said.
It did not specify who was responsible for the shelling.