The US warned on September 29 of an “unprecedented” buildup of Serbian troops and military equipment along the Kosovan border. Officials urgently called upon Belgrade to withdraw the forces immediately.

Nato said in a statement that it is bolstering its presence in Kosovo as tensions increase. Serbia’s military buildup was reported days after a Kosovan police officer was shot dead and another border policeman was injured in a gunfire exchange in the predominantly ethnically Serbian northern region of the country. 

The Serbian government has denied being behind the attack, but Milan Radoicic, deputy head of the main party of Serbs in Kosovo, the Serb List, said on September 29 that he assumed full responsibility for the deadly clashes in the village of Banjska in northern Kosovo. He said he acted alone, without informing Belgrade.

The spokesperson for the US national security council, John Kirby told reporters on September 29 there is a “large Serbian military deployment” along the border with Kosovo. 

“We are monitoring a large Serbian military deployment along the border with Kosovo that includes an unprecedented staging of advanced Serbian artillery, tanks and mechanised infantry units,” Kirby said. 

“This is a very destabilising development, which has occurred over the past week, and we are calling on Serbia to withdraw forces from the border and lower tensions,” the spokesperson added. 

Nato’s North Atlantic Council met on September 29 to discuss the situation in Kosovo amid increasing tensions in the north. 

The alliance announced that more forces were authorised for Kosovo the previous day, and the security presence will be stepped up further if needed. 

Nato has already increased its presence in Kosovo since May, when dozens of people including Nato’s Kosovo Force (KFOR) peacekeepers were injured in clashes between Serb protesters and law enforcers. 

"#NATO Allies met today & expressed deep concern about tensions in northern #Kosovo. NATO’s #KFOR mission will always take the necessary actions to maintain a safe & secure environment & freedom of movement for all,” wrote Nato Secretary General Jens Stoltenberg on X (formerly Twitter). 

“NATO’s KFOR mission maintains a visible and agile presence across Kosovo. We will always take all necessary actions to maintain a safe and secure environment and freedom of movement for all people living in Kosovo. We do so impartially and in line with our UN mandate,” a Nato statement said. 

“Since May, we have enhanced KFOR’s presence and posture. Only yesterday the North Atlantic Council authorised additional forces to address the current situation … We stand ready to make further adjustments to KFOR’s posture as required.” 

Nato also called on all parties to urgently de-escalate. “We continue to urge Belgrade and Pristina to engage in the EU-facilitated dialogue, as the only way to resolve outstanding issues and reach solutions that respect the rights of all communities. This is key for lasting security in Kosovo and stability in the region,” the statement said. 

In an attempt to calm the situation, Secretary of State Antony Blinken held a talk with Serbian President Aleksandar Vucic, while Sullivan discussed the situation with Kurti. 

“I had a long and not easy phone conversation with the US Secretary of State @secblinken, whom I learned in detail about the facts regarding the latest events in Kosovo and Metohija,” Vucic wrote on Instagram. 

“We agreed that it is necessary to de-escalate, as well as regarding the greater role of KFOR, and Serbia will always and certainly support that role.”

Meanwhile, Kurti confirmed talks with Sullivan in a post on Twitter. “Encouraging call w/ @POTUS NSA @jakejsullivan. Thanked him for support of border security & requested increased assistance against Serbia's warfare plans. Assured him of continued Kosova Police cooperation w/ KFOR & that our commitment to protect all citizens is unshakable,” Kurti wrote.

Kosovo, predominantly inhabited by ethnic Albanians, unilaterally declared independence from Serbia in 2008, following the 1998-99 conflict with Serbian forces, which ended with Nato attacks on Serbian targets.

The recent buildup in tensions has jeopardised the EU-mediated negotiations between Belgrade and Pristina aimed at enhancing their bilateral relations. These talks had already hit a standstill following the unsuccessful round of discussions on September 14.