Ukraine's government threatened to block the convoy if the cargo could not be inspected, and Kiev announced it was organizing its own shipment of humanitarian aid.
The Russian convoy of more than 200 vehicles had been parked at a military depot in the southern Russian city of Voronezh since late Tuesday amid disagreement over how and where the aid could be delivered to Ukraine, where government troops are battling pro-Russia separatists.
Today the white trucks, some flying the red flag of Moscow city and accompanied by green military vehicles, travelled down a winding highway through sunflower fields and rolling green hills.
The route suggested Russia was intent on not abiding by a tentative agreement to deliver aid to a government-controlled border checkpoint in the Kharkiv region, where it could more easily be inspected by Ukraine and the Red Cross.
Moscow has insisted it coordinated the dispatch of the goods, which it says range from baby food and canned meat to portable generators and sleeping bags, with the international Red Cross.
Andriy Lysenko, a spokesman for Ukraine's National Security and Defense Council, said Ukraine would be forced to act if the Russians refused to allow inspection of its cargo.
Although the border crossing where the trucks were likely to pass remained in rebel hands, areas south of Luhansk have been bitterly fought over and the location of forces is in constant flux.
It's unclear whether all the towns and villages on the road from the border to Luhansk are controlled by pro-Russian separatists.
ICRC spokeswoman Anastasia Isyuk said talks between the organization, Ukraine and Russia were continuing, but she could not confirm where the Russian convoy was headed.