Rebel forces in eastern Ukraine are pushing to capture the government-held airport in the city of Donetsk.
The Ukrainian military said on October 2 that pro-Russian separatists continued an offensive begun the previous day, on "a broad front."
Army spokesman Vladyslav Seleznyov said Ukrainian forces repelled four attacks on the airport during the evening of October 1, destroying a tank and killing seven rebels.
The rebels used tanks, multiple-launch rocket systems, artillery, and mortars, Seleznyov added, resuming their attacks on the morning of October 2.
Aleksandr Zakharchenko, prime minister of the self-proclaimed "Donetsk People's Republic," was quoted as saying on October 1 that separatist forces control "90 percent of the airport's territory" and plan to have it fully under their control "in two or three days at most."
The airport has been a focus of fighting between government forces and the insurgents despite a September 5 cease-fire in the conflict which has killed more than 3,000 people since April.
WATCH: Ukrainian troops on the front line in Chernokhino, halfway between Luhansk and Donetsk in eastern Ukraine, reported coming under mortar and artillery attack despite the cease-fire. Speaking on September 30, they said they had suffered two dead and more than 10 wounded over the previous 10 days.
Meanwhile, shelling has repeatedly been reported in the rebel-held city of Donetsk.
On October 2, the Interfax news agency reported that the city became the target of an artillery strike a day after about 10 people were killed in shelling there.
Three people were reported killed on October 1 when a shell exploded on a school playground, while several others died when a shell hit a minivan on a nearby street.
The blasts occurred as pupils returned to school after the start of the school year was postponed from September 1 due to fighting.
Meanwhile, diplomatic pressure on Russia continued as German Chancellor Angela Merkel told Russian President Vladimir Putin via phone on October 1 that Moscow has a duty to exert influence on the separatists in Ukraine.
According to a German government spokesman, the two leaders expressed concerned that violence was still being used in Ukraine every day.
Merkel said the border between Ukraine and Russia needed to be monitored and the Organization for Security and Cooperation in Europe (OSCE) had a big role to play in that.
Earlier, new NATO Secretary-General Jens Stoltenberg said the cease-fire in Ukraine presented the chance of a resolution to the Ukraine crisis but Russia still had the power to disrupt the country.
"The cease-fire in Ukraine offers an opportunity but Russia maintains its ability to destabilize Ukraine. Russia remains in breach of international law," Stoltenberg told his first news conference in Brussels as NATO leader.
Stoltenberg also had conciliatory words for Russia, saying he saw no contradiction between aspiring for a constructive relationship with Moscow and being in favor of a strong NATO.