The United States warned on Friday of a “major Serbian military deployment along the border with Kosovo,” at a time when tensions between Pristina and Belgrade are very high.

Washington “asks Serbia to withdraw (its) troops,” declared a White House spokesman, announcing a greater NATO presence in Kosovo.

In Belgrade, Serbian President Aleksandar Vucic informed the media of an exchange held on Friday with the head of US diplomacy, Antony Blinken, and accused Washington of telling “falsehoods”, without explicitly denying the presence of troops. Serbs near the border with the territory.

He stated that he “has not signed” an order for the “highest level of combat readiness” of Serbian forces, adding: “We do not have even half the troops that we had two or three months ago” in the area near the border with Kosovo.

Relations between Belgrade, which continues to refuse to recognize the independence declared by Pristina in 2008, have gone from crisis to crisis, but the latest outbreak of tensions is the most serious for several years.

On Friday, NATO said it was ready to increase the size of KFOR, the force it deploys in Kosovo, to “cope with the situation” following the attack by a heavily armed commando in the north of the country last Sunday.

The military alliance did not specify the type of forces that could be deployed, but the British Ministry of Defense said that a battalion of between 500 and 650 men had been made available to KFOR, if necessary.

The White House has seen “the unprecedented deployment of sophisticated artillery, tanks and infantry units” to the Kosovo border, National Security Council spokesman John Kirby said, adding that these troop movements had occurred “along from last week”.

He declined to comment on Serbia’s “intentions” or the risk of a possible invasion of Kosovo. John Kirby stated that Antony Blinken had called the Serbian President to express American “concern” and “underscore the need for an immediate reduction in tensions and a return to dialogue.”

US National Security Advisor Jake Sullivan met with Kosovo Prime Minister Albin Kurti.

In a brief statement on Wednesday, Belgrade said Defense Minister Milos Vucevic had visited, together with the chief of the General Staff of the Armed Forces, General Milan Mojsilovic, “the area of ??deployment of part of the army units Serbian”, without giving more details.

Relations between Serbia and Kosovo remain strained two decades after a deadly war between Kosovo independence guerrillas and Serbian forces, which only ended with a NATO bombing campaign.

A Kosovo Albanian police officer died on Sunday in an ambush in northern Kosovo, where Serbs are the majority in several cities. A shootout occurred between Kosovo police special forces and a heavily armed commando group, whose members were identified as Kosovo Serbs.