The Red Cross is to lead an international humanitarian aid operation into Ukraine’s rebel stronghold of Luhansk.
It is believed the mission will be with assistance from Russia, the European Union and the United States.
Earlier Russia had said only it was accompanying a convoy to Luhansk and surrounding areas. That is where thousands of people have been without water, electricity and medical aid for nearly two weeks.
Russia initially announced a deal had been reached with the Red Cross but the humanitarian organisation insisted it has strict guidelines on maintaining its neutrality.
Latest reports say a convoy of 280 vehicles have already left Moscow for Ukraine.
Kyiv, NATO and the West have warned Russia against taking any unilateral action.
They have said any attempt to send in military personal with the aid mission would be seen as an invasion.
Elsewhere in eastern Ukraine and pro-Russian separatists in the city of Donetsk say they are planning a major counter-attack.
Ukrainian government forces have recently been been closing in on the few remaining pro-Russia rebel strongholds in the region.