One police officer and three attackers were killed after gunmen stormed the village of Banjska in northern Kosovo.

On Sunday, the gunmen stormed the village of Banjska battling police and barricading themselves into a Serbian Orthodox monastery. Police retook the monastery later in the day after three attackers and one police officer were killed.

Armed police on Monday searched houses in Banjska for any of the estimated 30 gunmen who might not have fled, a police source told the Reuters news agency. The village remained sealed off to journalists.

Kosovo Interior Minister Xhelal Svecla said six wounded members of the armed group had been hospitalised in the southern Serbian city of Novi Pazar, near Kosovo’s northern border.

“We are demanding from Serbia to hand these men over to Kosovo authorities as soon as possible, to face justice for their terrorist acts,” in addition to any others who had escaped to Serbia, Svecla told reporters.

Kosovo Police General Director Gazmend Hoxha said the operation was the largest police action in the country since the Kosovo War in 1999.

“Police operations are still continuing, and so far, weapons of various calibres, rocket launchers, explosives, detonators, one heavy armoured vehicle, 24 automobiles, two 4×4 motorcycles, 150 explosives, three drones, 30 AK47 weapons have been found in and around the monastery in Banjska,” Hoxha said.

“Also, six machine guns, 29 mortars, over 100 military uniforms, as well as work tools such as pickaxes, shovels, hand saws, medicine, and food that will last for a long time were found.”

‘Nothing can be the same anymore’

Kosovo Prime Minister Albin Kurti on Monday said “nothing can be the same anymore” after Sunday’s attack.

“Afrim Bunjaku was killed during an attack on Kosovo policemen and on our state itself by a group heavily armed and heavily equipped, professionally trained and planned, politically supported, materially financed and logistically supported by Serbia,” Kurti said.

While ethnic Albanians comprise the vast majority of Kosovo’s 1.8 million people, 50,000 Serbs in its north reject Kosovo statehood and see Belgrade as their capital, 15 years after Kosovo declared independence following a guerrilla uprising. Serbia does not recognise Kosovar independence.

Serbian President Aleksandar Vucic has denied Kurti’s allegations that Belgrade orchestrated the attack. He accuses Kurti of inciting violence by blocking the creation of an association of Serb municipalities to give more autonomy to Serbs – approved by an earlier Kosovo government in 2013 – and by launching frequent police raids in the north.

Kurti has said granting northern Serbs significant autonomy would effectively partition Kosovo along ethnic lines.

In a statement, US Secretary of State Antony Blinken called on the Kosovar and Serbian governments “to refrain from any actions or rhetoric which could  further inflame tensions”.

Meanwhile, Russia defended its ally Serbia, saying Kosovo’s government was to blame for the incident, warning that the “bloodshed” could spiral out of control.

“There is no doubt that yesterday’s bloodshed is a direct and immediate consequence of the course of the so-called ‘Prime Minister’ Albin Kurti to incite conflict,” the Russian foreign ministry said, warning that attempts to escalate the situation could bring “the entire Balkan region to a dangerous precipice”.

Moscow said the Kosovo police force had “long ago discredited itself due to systematic punitive actions against the Serb community”.