Ukraine said Friday the entry of Russian aid trucks onto its territory was a "flagrant violation" of international law and it appealed to the international community to condemn Russia's actions as illegal and aggressive.
The foreign ministry said in a statement that, while Ukrainian authorities had not given the convoy permission to enter, it had been allowed to cross the border to avoid further provocative action.
Earlier, Kiev said Russia had launched a direct invasion of its territory by sending the convoy into eastern Ukraine, where pro-Russian rebels are fighting government forces.
"We call upon all international partners to unite in decisively condemning Russia's illegal and aggressive actions," the ministry said in a statement.
"In order to avoid provocations we gave all the necessary commands for the safe passage of the convoy ... We consider this another flagrant violation by Russia of the main principles of international law."
According to the Ukrainian border service, 145 trucks had crossed the border from Russia by 1030 GMT.
Ukrainian state security chief Valentyn Nalivaychenko told journalists that the convoy's entry represented a "direct invasion" of Ukraine by the Russian Federation.
He said Ukrainian forces would not attack it, though its security could not be guaranteed by Kiev because of fighting by pro-Russian separatists in the east, where the convoy was moving towards the Luhansk region.