British troops have begun patrolling the Kosovo-Serbia border.

The patrol comes as part of NATO peacekeeping presence being bolstered amid concern that the former wartime foes could return to open conflict following a series of violent incidents in recent months.

Report says the North Atlantic Treaty Organization sent hundreds of additional forces to Kosovo from Britain and Romania after a battle between the authorities and armed Serbs holed up in a monastery turned a quiet village in northern Kosovo into a war zone on September 24.

One police officer and three gunmen were killed in the village of Banjska in what was seen as the worst violence since Kosovo declared independence from Serbia in 2008.

Kosovo accused Serbia of providing financial and practical support for the gunmen, which Belgrade denies.

Meanwhile, NATO has sent 1,000 extra troops to the region, bringing its presence there to 4,500 peacekeepers from 27 countries.

British soldiers are now being deployed in 18-hour shifts in freezing conditions to make sure no weapons or armed groups enter Kosovo.

“Currently we are here on a routine patrol, which consists of understanding patterns of life, gaining intelligence on any illegal or suspicious activity that then gets fed back to KFOR (NATO mission) and higher,” Lieutenant, Joss Gaddie from the British Army said.

However, during a visit on Monday to the western Balkans, NATO Secretary-General, Jens Stoltenberg said the organization is reviewing whether a more permanent increase of forces was needed “to ensure that this doesn’t spiral out of control and creates a new violent conflict in Kosovo or in the wider region.”

Kosovo, which has an ethnic Albanian majority, declared independence from Serbia in 2008 after a guerrilla uprising and a 1999 NATO intervention.

Report says round five percent of the population in Kosovo are ethnic Serbs, of which half live in the north and refuse to recognize Kosovo independence and see Belgrade as their capital. They have often clashed with Kosovo police and international peacekeepers.

For more than two decades many ethnic Serbs have refused to register vehicles with Kosovo car plates, using their own system instead which is seen as illegal by Pristina.

Prime Minister, Albin Kurti’s government has set a December 1 deadline for around 10,000 motorists to register their cars with Kosovo numbers or face heavy penalties. A similar request sparked violence last year.

REUTERS/Christopher Ojilere