Russian-backed rebels and Ukrainian government troops fought pitched battles Monday for control of Donetsk airport, while residential areas nearby were caught in intensive crossfire.

The airport, reduced to a hulking wreck by months of heavy fighting, has been the epicenter of hostilities due to its symbolic importance and strategic location on the edge of the main rebel-controlled city.

The airport has become a symbol of Ukrainian combat valor and its loss would be a major blow to national pride.

The rebels say they have fully seized the airport in recent fighting, but Ukrainian officials reject the claim. They say Ukrainian troops are still holding out in the wreckage of the new terminal, a steel-and-glass showcase for the UEFA Euro 2012 soccer championship hosted by Ukraine.

Three Ukrainian servicemen were killed and 66 wounded in the previous 24 hours, military spokesman Andriy Lysenko told reporters, but he would not say how many of those casualties occurred at the airport.

On Monday, the rebels blew up part of the new terminal, wounding many Ukrainian troops with debris, Yuriy Biryukov, an adviser to Ukrainian President Petro Poroshenko, wrote on his Facebook account. He said some wounded soldiers were evacuated from the airport but did not say how many troops remained.

It was impossible independently to determine whose forces were currently in control of various sections of the airport.

In the long term, the government fears the separatists could use the airport to expand their control over eastern Ukraine, bypassing border controls and creating an air supply route with Russia.

The separatists increased the stakes last week by successfully taking over large sections of the airport before the Ukrainians unleashed a counter-offensive.

"All attempts of the Ukrainian army to take the airport and to get revenge for the defeat of the last year... have failed," rebel leader Alexander Zakharchenko told reporters Monday in Donetsk. He accused Ukraine of using rocket and artillery fire with an intensity that rebel forces had "never experienced before."

Lysenko, however, said the weekend fighting had returned control over the airport to the military.

The city of Donetsk was shaken by heavy artillery fire over the weekend as the airport battle raged.  On Monday, a shell hit the city's Central Clinical Hospital No. 3, blowing out windows but causing no deaths. All the patients were evacuated to other hospitals. Sporadic explosions were also heard Monday from the direction of the airport.

Lysenko said according to September's cease-fire deal in September, the airport was to be left under Ukrainian government control. Russia and the separatists dispute this.

The U.N. estimates more than 4,700 people have been killed in the fighting in eastern Ukraine since April.

Ukraine and the West have accused Russia of helping the rebels in the east with troops and weapons. Moscow has denied the charge, but acknowledged that some Russians have joined the insurgents.

In Brussels, European Union foreign ministers ruled out any easing of the sanctions imposed on Russia for its actions in Ukraine. Dutch Foreign Minister Bert Koenders said Monday the fighting around Donetsk airport showed "this is no time to talk about the easing of sanctions."

Russia has shown "no political will, no movement on the ground, so no reason to change policy," Lithuanian Foreign Minister Linas Antanas Linkevicius said.