More than a dozen trucks said to be carrying aid from Russia have been allowed to approach the border with Ukraine.
Around 280 lorries are being held up while they await inspection to verify that they do not contain military equipment.
Moscow says the trucks are carrying water, food and medicine.
Earlier, Pro-Russian separatists shot down a Ukrainian fighter jet in the Luhansk area of eastern Ukraine.
A Ukrainian military spokesman said the pilot ejected - and has been taken to safety.
