Fighting around the symbolically and strategically important Donetsk airport area in rebel-held eastern Ukraine has intensified with the failure of ceasefire talks among leaders of France, Germany, Ukraine and Russia. The battle over control of the area has become one of the fiercest clashes since fighting between pro-Russia separatists and the army began in May. At the airport, the ceasefire, agreed upon six weeks ago, has been widely ignored by both Ukrainian and pro-Russian fighters.

While the ceasefire, signed Sept. 5 in Minsk, Belarus, has been observed around other parts of the Ukraine, the Donetsk airport -- which serves the capital of the self-proclaimed, rebel Donetsk Republic -- has seen continuous bombardment with mortars and response artillery fire, making it clear neither side intends to end hostilities.

Olexander Motsyk, Ukraine’s ambassador to the U.S., said if rebels gain full control of the airport and the areas around it, they will try to operate aircraft.

"They [rebels] hope Russia will give them aircraft so they can have an air force there," Motsyk said. "We observe the ceasefire and do not shell positions of rebel forces except when they fire on our positions."

Rebel commander Mikhael Sergeyevich told USA Today he wants to hold the airport against Ukrainian forces, who he said were preparing an assault to try to recapture it.

Talks in Milan, Italy, had been aimed at getting both sides to abide by the ceasefire, but that now seems unlikely with Russian Foreign Minister Sergey Lavrov saying Russia will not accept conditions for ending sanctions.

“We respond very simply: We shall not agree to any criteria or conditions,” Sergei Lavrov told the Wall Street Journal. “Russia is doing more than anyone else to resolve the crisis in Ukraine.”