Kosovo said on Saturday it had closed two border crossings with Serbia after protesters on Serbian soil partially blocked roads and turned back passengers with Kosovo documents in protest over recent tensions in Kosovo's volatile north.

A small group of protesters gathered a few kilometres inside Serbia, near at least three border crossings, and were checking whether drivers had Kosovo-issued travel documents.

"Masked extremists groups inside Serbian territory are selectively and with a fascist approach stopping citizens who use Serbia as transit," Kosovo's interior minister, Xhelal Svecla, said on his Facebook page, announcing the closure of crossings in Merdare and Bernjak.

Four other border between the Balkan neighbours remained open.

The group was protesting against Pristina's recent actions in northern Kosovo, mainly inhabited by ethnic Serbs, which closed Belgrade-run parallel institutions.

Some 50,000 Serbs live in that area and, like Serbia, do not recognise Kosovo's independence. They consider Belgrade their capital.

In the past two years, northern Kosovo has experienced its worst ethnic tensions since the Albanian-majority country declared independence in 2008 after a years-long guerrilla uprising against repressive Serbian rule.

Although Kosovo is recognised by more than 100 countries, Serbia deems it part of Serbian territory. It accuses Kosovo's central government of trampling on the rights of ethnic Serbs and denies accusations of whipping up strife within its neighbour's borders.