A spokesman for the international KFOR forces, which guarantees the security of the former Serbian province, confirmed the deployment and told AFP it was part of "normal exercises all around Kosovo".

"We have a couple of convoys moving around. One of them is going today to the north," said KFOR spokesman Vincenzo Grasso, adding that there was no reason for alarm.

During the morning around 50 KFOR vehicles moved through the divided city of Mitrovica and headed north in the direction of Leposavic, a mostly Serb municipality in Kosovo, an AFP correspondent said.

Zoran Todic, the top official in Leposavic, confirmed their presence and said the troops were "heavily armed and equipped to prevent demonstrations".

KFOR troops were later seen returning south, according to an AFP correspondent.

On Twitter, the peacekeeping mission's official account said it was conducting "a regular training activity to keep ready to be rapidly deployed all over Kosovo" in line with its mandate.

The exercise comes during a tense moment between Kosovo and Serbia, which fiercely opposes Pristina's plans to turn its crisis response force into a full-fledged army.

Belgrade refuses to recognise the independence Kosovo declared in 2008, a decade after a brutal guerilla war, and has maintained strong links with Serb communities there.

Pristina has struggled to exercise its authority in those Serb enclaves, who are also against the creation of an army.

In 2012, there were violent riots in northern Kosovo after Pristina authorities sent police to take control of two border crossings with Serbia.

KFOR, which has more than 4,000 troops, has been deployed in Kosovo since the end of the 1998-99 war between Serb forces and Kosovo Albanian separatists, which left more than 13,000 dead.

Late Thursday, without establishing a link with inter-ethnic tensions, Kosovo police said it had found about 15 kilogrammes (33 pounds) of explosive outside of Pristina, near a Serb monument commemorating the 1389 Kosovo Battle, seen by many as the origin of the Serb national identity.