The contents of the trucks -- which Russia says consists of 340 tons of canned meat, 649 tons of water and 62 tons of baby food -- is destined for the city of Luhansk, where combat between Ukrainian military troops and pro-Russian separatists has left the city isolated and without electricity or clean water.
The convoy left the military base in Voronezh, Russia, early Thursday, where it was parked for over a day, as the Kiev government objected to its arrival in Ukraine without inspection by border guards and international observers. The convoy was first dispatched on Tuesday.
Russia and Ukraine initially agreed the trucks would cross the border into territory under government control, but the route of the trucks was changed so they could directly enter Luhansk. The latest diplomatic negotiations indicate the convoy will be inspected before it arrives on Ukrainian soil, but no timetable or border crossing point have been announced.
Ukrainian military spokesman Andriy Lysenko said Thursday "all forces available" would be used to block the convoy if it attempted entry into Ukraine without a prior inspection of its contents.
"This convoy has to be checked to see what cargo it is carrying. This has to be controlled by Ukrainian border guards," Lysenko said, adding Red Cross representatives "need to learn the exact contents of this cargo."
Diplomatic progress came as Russian President Vladimir Putin, in a speech in Crimea's city of Yalta, said, "We will do everything we can to help secure an end to this conflict as soon as possible, so that there will be no more bloodshed in Ukraine," the Russian news agency Interfax reported.
Putin's apparently conciliatory comments are his latest in a series of remarks indicating a desire for peacemaking, although Russia has continued to send troops and military equipment to the border with Ukraine. Western powers have claimed Russia is supporting separatists within Ukraine, intent on destabilizing the country, a charge Putin denies.