Despite the ceasefire agreement, renewed fighting flared up on Saturday in eastern Ukraine between pro-Russian rebels and government forces, while Moscow sent a second convoy of trucks into Ukraine without Kiev's consent.
Ukraine's military operation said in a statement that it had successfully repelled a rebel attack on the government-held Donetsk airport on Saturday, which came under artillery fire from rebel positions late on Friday.
"Many rebels backed by six tanks launched an assault against the airport on Friday which was heroically repelled by the soldiers," the military said.
Despite the truce imposed last week, continuous rocket fire could be heard overnight in Donetsk. A statement posted on the city council website said that shells had hit residential buildings near the airport, although no casualties were reported.
A column of three GRAD rocket launchers - all its rockets still in place - was seen moving freely through the rebel-held city on Saturday morning.
Donetsk, the biggest city in the conflict zone, has been in rebel hands for months although government forces have dug in at the airport.