Kosovo postponed the implementation of new border rules after police had to close two border crossings with Serbia on Sunday due to rising tensions.

The police said they were forced to shut the Bernjak and Jarinje border crossings after demonstrators shot at authorities and blocked roads.

The protesters were angry about a new rule that would have forced all people entering Kosovo with Serbian IDs from Monday to replace them with a temporary document during their stay in the country. A similar rule is applied by Belgrade authorities to Kosovars who visit Serbia.

The government also said ethnic Serbs who have registration plates issued by Serbia would have to change them for Kosovo license plates within two months.

Following tensions on Sunday evening and consultations with EU and US ambassadors, Pristina said it would delay its plan for one month, and start implementation on September 1.

EU foreign policy chief, Joseph Borell, welcomed the decision and urged demonstrators to remove all roadblocks immediately.

Why are the Serbs resisting? 

Some 50,000 ethnic Serbs living in the country's north use license plates and documents issued by Serbian authorities.

They do not recognize Kosovo's right to impose rules and regulations.

Serbian President Aleksandar Vucic said he situation in Kosovo had never been "more complex" for Serbia and ethnic Serbs.

"The atmosphere has been brought to a boil," Vucic said, warning that "Serbia will win" if Serbs are attacked.

Kosovo Prime Minister Albin Kurti accused Vucic of igniting "unrest".

"The following hours, days and weeks can be challenging and problematic," Kurti said on Facebook.

The new border rules comes almost a year after Kurti gave up imposing similar rules due to similar protests.

Ethnic Serbs staged daily protests and blocked the traffic at the two border crossings.

NATO ready to intervene

Serbia does not recognize Kosovo's independence, and tensions between the two are now at their highest in years.

On Sunday NATO said it was ready to intervene if "stability is jeopardized"

The alliance maintains peace with 3,770 troops on the ground in Kosovo.

It said it would "take whatever measures are necessary to keep a safe and secure environment in Kosovo at all times."

It encouraged the parties to continue talks. 

EU-brokered talks between the two countries launched over a decade ago, but have so far failed to achieve normalization of their ties.

Last month Kosovo said it would make an official application to join the European Union at the end of the year.

lo/wd (Reuters, AFP, dpa)