Ukraine's military said Saturday it has successfully defended the government-held airport in Donetsk from an attack by pro-Russian rebels.
Plumes of black smoke hung over the airport after it came under artillery fire late on Friday, in one of the biggest battles since a fragile ceasefire was declared.
Ukrainian authorities also admitted for the first time since the cease-fire started last week that they have inflicted casualties on the rebel side.
Continuous rocket fire could be heard overnight in Donetsk. A statement on the city council website said that shells hit residential buildings near the airport, although no casualties were reported.
A column of three Grad rocket launchers — all its rockets still in place — could be seen moving freely through the rebel-held city Saturday morning.
In the other regional capital, Luhansk, one of the worst-hit cities where tens of thousands have been without water, electricity or phone connections for weeks, streets were calm as Russian drivers unloaded aid packages into local warehouses after crossing into Ukrainian territory overnight.
The 200 trucks are the second Russian humanitarian aid convoy to enter Ukraine since the conflict began. The Kyiv government protested last month's larger Russian relief convoy as it crossed the border uninvited, but Ukraine officials remained largely silent Saturday as the mission unfolded.
The Organization for Security and Co-operation in Europe Observer Mission at the Donetsk checkpoint reported that the 220 vehicles in the convoy were not inspected by Ukrainian officials or the Red Cross.
Russia's Emergencies Ministry says the humanitarian cargo includes food, generators and water purifiers.
Meanwhile, Ukraine's prime minister said Russian President Vladimir Putin wants to destroy Ukraine as an independent country, despite a truce deal.
Speaking at an international conference Saturday in Kyiv, Arseniy Yatsenyuk said Putin's goal is to take all of Ukraine, a key part of the former Soviet Union.
Yatsenyuk praised the new wave of economic sanctions imposed on Russia by the European Union and the United States, whose governments have expanded punitive measures targeting Russia's energy, financial and defense sectors in a new push to punish Moscow for its role in the Ukraine crisis.
Hours after the penalties took effect Friday, Moscow vowed to retaliate. The Russian Foreign Ministry called the new U.S. measures a "hostile step in line with the confrontational course taken by the U.S. administration."
The new sanctions close down Western aid to Russia's burgeoning deepwater Arctic offshore and shale oil exploration.
They also target five defense companies, and the arms and technology company Rostec, as well as several leading banks, including Russia's largest, Sberbank.
Senior Obama administration officials stressed that the United States will roll back the new penalties if Moscow and the pro-Russian separatists Russia is accused of supporting fully implement a cease-fire deal reached earlier this month.
European Council President Herman Van Rompuy has said the EU sanctions could also be amended, suspended or repealed after the EU reviews the state of the cease-fire at the end of September.
Putin on Friday called the EU sanctions "strange," saying they undermine the "peace process" in eastern Ukraine.