Kosovo will delay the implementation of new rules after tensions with Serbia rose over the weekend, prompting the NATO-led mission in the Balkan country to pledge it was “prepared to intervene if stability is jeopardized.”

Fears of Balkan instability grew on Sunday as ethnic Serbs blocked roads in protest over regulations requiring Serbs in northern Kosovo to use Pristina-issued car license plates and for visitors from Serbia to receive documents issued by Kosovo.

“The government of the Republic of Kosova forcefully condemns the obstruction of roads in the north of Kosova and the firing of weapons by armed persons there today,” Kosovo’s Prime Minister Albin Kurti said in a statement late Sunday. Police in Kosovo said that shots were fired “in the direction of police units” but no one was wounded.

Senior officials from Kosovo’s government have spoken with American and EU officials, Kurti said, adding that his government “pledges to delay the implementation” of the new rules until September 1 “once all barricades are removed and complete freedom of movement is restored to all roads in the north” of Kosovo.

After war in the late 1990s, Kosovo declared its independence in 2008, but Pristina and Belgrade have been attempting to negotiate over technical issues through an EU-led dialogue since 2011. The spat over license plates already fueled tensions last year.

“We pray and ask for peace,” Serbia’s President Aleksandar Vučić tweeted Sunday night. “If they dare to persecute and kill Serbs, Serbia will win,” he said.

As tensions escalated on Sunday, the Kosovo Force (KFOR), a NATO-led international peacekeeping mission, reiterated its commitment to preserving stability.

“The overall security situation in the Northern municipalities of Kosovo is tense,” KFOR said in a statement, adding that the “mission is monitoring closely and is prepared to intervene if stability is jeopardized, in accordance with its mandate.”

“Our NATO-led KFOR mission is fully focused on the daily implementation of its UN mandate to ensure a safe and secure environment and freedom of movement for all the people of Kosovo,” the mission said.

“KFOR maintains a visible and agile posture on the ground, and the KFOR Commander is in contact with all of his main interlocutors, including the representatives of the Kosovo security organizations and the Serbian Chief of Defense,” it noted, adding that, “KFOR will take whatever measures are necessary to keep a safe and secure environment in Kosovo at all times, in line with its UN mandate.”

Kosovo’s international partners welcomed Pristina’s move to calm the situation.

“Welcome Kosovo decision to move measures to 1 September,” the EU’s foreign policy chief Josep Borrell tweeted. “Expect all roadblocks to be removed immediately,” he said.

“Open issues,” Borrell said, “should be addressed through EU-facilitated dialogue.”

Defense Europe Kosovo Nato Security Serbia