A Kosovo court on Tuesday remanded two suspected gunmen into custody after they were arrested at the weekend during a firefight and standoff with police near the border with Serbia. 

The court's decision came days after the killing of a police officer during an ambush and an ensuing gunbattle at a monastery in the village of Banjska, marking one of the gravest escalations in Kosovo for years.

"The Basic Court in Pristina has set the measure of 30 days detention for the two arrested who are suspected of serious crimes against the constitutional order and security of the Republic of Kosovo and committing terrorist acts," Mirlinda Gashi, a spokeswoman for the court in the capital Pristina, told AFP.

A third suspect was remanded a day earlier by the court.

The court's decision followed an announcement in Serbia that an official day of mourning would be held on Wednesday to commemorate the "tragic events in Kosovo".

The announcement mirrors a similar statement released by the leading political party for Serbs in northern Kosovo calling for several days of mourning for the gunmen killed in the clashes. 

The party said flags at Serb institutions in Kosovo would be lowered to half mast, while all entertainment events would be cancelled. 

Questions remained over the fate of the remaining gunmen who participated in the attack, with Kosovo authorities saying at least six had escaped across the border into Serbia. 

Sunday's attack came more than a week after talks between the leaders of Serbia and Kosovo on improving ties failed to make a breakthrough during EU-mediated negotiations in Brussels.

Tensions in the troubled north of Kosovo have been smouldering for months, following the Pristina government's decision in May to install ethnic Albanian mayors in four Serb-majority municipalities there.  

The move triggered one of the worst bouts of unrest in the north in years. 

Demonstrations followed, as well as the arrest by Serbia of three Kosovar police officers and a riot by Serb protesters which saw more than 30 NATO peacekeepers injured.

The clash in the north is just the latest incident to rock the area since Kosovo declared independence from Serbia in 2008. 

Belgrade -- and key allies China and Russia -- have refused to recognise Kosovo's independence.

Animosity between Kosovo and Serbia has persisted since a war between Serbian forces and ethnic Albanian insurgents in the late 1990s that drew NATO intervention against Belgrade.

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