The EU has called for a Russian relief convoy heading for a rebel-held zone in eastern Ukraine to be vetted by the Red Cross.
Up to 287 vehicles carrying food, water and other aid are expected to reach the Ukraine border from Russia on Wednesday afternoon despite outrage from Kyiv.
Russian Foreign Minister Sergey Lavrov says the route was agreed with Ukrainian authorities.
“We have taken into account requests from the Ukrainian side on all aspects of this operation including the route that was suggested by Kiev, despite the fact that it is a very long detour compared to other routes of humanitarian aid delivery.”
Kiev says Russia is using the aid trucks as an excuse for an invasion and says it will refuse entry.
“In Donbass they are trying to use the pretext of humanitarian aid and assistance, and it seems they are just running out of excuses for their aggression,” said Ukrainian Deputy Foreign Minister Danylo Lubkivsky.
Ukrainian forces have been closing in on pro-Russian rebels in the east in recent days.
Thousands of people are believed to be short of water, electricity and medical aid in Donetsk and the border town of Luhansk after bitter fighting involving air strikes and missile attacks.