DONETSK, Russia (AP) — Some of the trucks in a Russian aid convoy that entered Ukraine in a move denounced by Kiev as an invasion are returning to Russia.

An Associated Press reporter saw four of the trucks waiting Saturday morning at the border crossing in the Russian town of Donetsk. It could not be determined if the trucks were carrying any cargo.

The convoy of some 260 trucks drove Friday into Ukraine, headed for Luhansk, a city in eastern Ukraine hard-hit by weeks of fighting between Ukrainian forces and pro-Russian rebels.

The Ukrainian government and Western countries said they suspected that the convoy could be used by Russia to smuggle supplies and reinforcements for rebel fighters.