The commitment comes as Kosovo police announced they had closed two border crossings in the volatile north after local Serbs blocked roads and fired at police in protest. Locals were angered by an order to change Serbian car plates to Kosovo plates within two months, sparking protests. NATO’s Kosovo Force (KFOR) said in a statement: “The NATO-led KFOR mission is closely monitoring and ready to intervene if stability is threatened in accordance with its mandate derived from Council resolution 1244 of 1999 Security of the UN. KFOR will take all measures necessary to maintain a safe and secure environment in Kosovo at all times, in accordance with the UN mandate.” Fourteen years after Kosovo declared independence from Serbia, some 50,000 Serbs living in the north use license plates and documents issued by Serbian authorities, refusing to recognize institutions under the capital, Pristina. Kosovo has been recognized as an independent state by more than 100 countries, but not by Serbia or Russia. Prime Minister Albin Kurti’s government said it would give Serbs a 60-day transition period starting Aug. 1 to obtain Kosovo license plates, a year after abandoning efforts to enforce them amid similar protests. The government added that from August 1, all citizens from Serbia visiting Kosovo will have to obtain an additional document at the border to be granted entry. A similar rule is applied by the authorities in Belgrade for Kosovars visiting Serbia. A Serbian army officer stands next to an Airbus H145M multi-role helicopter during an arms exhibition in Belgrade (AP) Protesters parked trucks filled with gravel and other heavy machinery on roads leading to the two border crossings, Jarinje and Bernjak, in a Serb-majority area. As a result, Kosovo police said they had to close the border crossings. “We urge all citizens to use other border crossing points,” police said on their Facebook page. Police said shots were fired “in the direction of police units, but fortunately no one was injured.” Police also claimed that angry protesters beat up several Albanians walking through the blocked streets and that some cars were attacked. Air raid sirens sounded for more than three hours in the small town of Northern Mitrovica, which is mainly inhabited by Serbs. A year ago, after local Serbs blocked the same roads over traffic signs, the Kosovo government deployed special police forces and Belgrade flew fighter jets near the border. Tensions between the two countries are now at their highest level in years, and Kosovo’s fragile peace is being maintained by a NATO mission that has 3,770 troops on the ground. Italian peacekeepers were also visible in and around Mitrovica on Sunday. The two countries committed in 2013 to a European Union-sponsored dialogue to try to resolve outstanding issues, but little progress has been made.