Prime Minister Albin Kurti alleged Serbia's defence minister Milos Vucevic heads the gang known as the "Novi Sad Clan".

He claimed the group was behind a 24 September attack on an Orthodox monastery in Banjska, northern Kosovo.

The incident saw 30 heavily armed Serbs barricade themselves in the building, before fighting broke out killing one police officer and three gunmen.

Mr Kurti also compared Serbian President Aleksandar Vucic to a mafia boss.

He did not offer any evidence for his claims, but he described the gang as a "paramilitary terrorist group".

Serbia's Defence Ministry said it "absolutely rejects the heinous and blatant lies told today by Kurti" and appealed to the international community to act to stop the "incendiary and dirty" campaign by Kosovo's leadership.

Kosovo has also accused Serbia of orchestrating the 24 September "act of aggression", which Belgrade denies, and called for EU sanctions.

Instead, Serbia accused an ethnic Serb leader from Kosovo, Milan Radoicic, for being behind the clashes.

Radoicic, a senior figure in Kosovo-Serb political party 'Serb List', was briefly detained, questioned and released in Serbia earlier this month.

Tensions between the two Balkan countries have continued to worsen, with September's incident being the most lethal since Kosovo declared independence from Serbia in 2008. Belgrade does not recognise the independence claim.

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'Dialogue must continue' - EU

In February, the EU put forward a 10-point plan to end the political crisis. Kurti and Vucic gave their approval but expressed reservations.

Meanwhile, EU special envoy Miroslav Lajcak urged Serbia and Kosovo to return to dialogue on normalising ties after last month's incident.

"The attacks in Banjska have changed many things and they need to be properly investigated... at the same time the dialogue must continue," the official said after meeting Kurti on Saturday.

"If there is not dialogue there might be a repetition of escalation."

NATO has also sent reinforcements to its Kosovo force, boosting 4,500 troops on the ground with an additional 200 troops from the UK and more than 100 from Romania.

On Facebook on Monday, Kurti proposed the EU and the US "create a special court" for the Novi Sad gang since Kosovo has no jurisdiction inside Serbia.