Serbian President Aleksandar Vučić said on Monday that Washington’s reports last week warning of a big build-up of Serbian troops on the Kosovo border “were not fully accurate.”

Speaking to CNN’s Christiane Amanpour in an interview, Vučić said: “We always appreciated all the reports that were coming from NSC (the National Security Council), (the) White House, and all the other institutions that are coming from the United States. But the real issue is that these reports were not fully accurate.”

The White House said last week that it was concerned, warning of an “unprecedented” build up of advanced Serbian artillery, tanks, and mechanized infantry units near the Kosovo frontier and calling for an “immediate de-escalation.”

“A year ago, we used to have 14,000 people at the administrative line with Kosovo. Few days ago, we used to have less than 8,400. Today we have 4,400, which is a regular number of people,” Vučić said.

“We always hear, and we always listened when our partners were asking us to de-escalate a situation and we did it this time, although there were no reasons for a big worry, because we didn’t need any kind of wars, any kind of clashes with NATO,” he added.

When asked why the Serbian government moved more troops to the border, Vučić said that Serbia’s army “follow the situation in the field, and they move our forces in a way that they believe it can be… the most useful and they have their own operations and everything else but I did not sign even a high alert for our army people.”

The long fractious ties between Serbia and neighboring Kosovo flared in late September, when 30 armed men opened fire on a Kosovar police patrol in the village of Banjska, in northern Kosovo, before barricading themselves inside an Orthodox monastery. The ensuing hourslong shootout left one Kosovar police officer and three gunmen dead.

Kosovo’s President Vjosa Osmani pointed the finger at Belgrade for inciting the violence.

A top Kosovo Serb politician, Milan Radoicic said this weekend that he took part in the gun battle, Reuters reported.

In a letter sent to Reuters by his lawyer, Radoicic, who is wanted in Kosovo and lives in neighboring Serbia, said he “personally prepared logistics for the defense of Serb people” and received no help from the Serb authorities. Radoicic is under US sanctions for suspected links to organized crime.

When asked if Radoicic will face accountability that the European Union is demanding, the Serbian president said: “Of course, Serbia will held accountable all the people that committed criminal deeds and that we might find on our territory … prosecutors will do their job,” but said that the issue started from the Serbs wanting to “protect themselves.”

“I’m not going to defend a killing of an Albanian police guy and I didn’t do it. I condemned that. But I’m saying that Serbs were arresting with no charges, home searches, evictions, expropriations, everything that was not in accordance with a Brussels agreement,” he added.

The clash was one of the worst since Kosovo declared independence from Serbia in 2008, almost a decade after a NATO bombing campaign drove out Serbian forces responsible for a brutal crackdown against ethnic Albanians, from Kosovo, leading to the end of the 1998-99 war.

More than 20 years on since the war, a fragile peace has been preserved in Kosovo, while Serbia continues to view it as a breakaway state and does not recognize its independence. Kosovo’s Serbs view themselves as part of Serbia, and see Belgrade as their capital, rather than Pristina.

The confrontation comes months after ethnic Serbs attacked dozens of NATO peacekeepers in the town of Zvecan, in northern Kosovo, in May. The clashes broke out after Serbian demonstrators tried to block newly elected ethnically Albanian mayors from taking office, following a disputed election in April.

Western leaders were quick to condemn the violent actions, urging both parties to de-escalate tensions. The violence has ratcheted tensions in the Balkan region as the EU and US mediators attempt to finalize yearslong talks to normalize ties between Serbia and Kosovo.

When asked about his thoughts on the Serbian tennis star Novak Djokovic leaving a political message on a TV camera lens at the French Open in May in response to violent clashes in Kosovo, the president said he believes Djokovic was expressing his feelings “from the bottom of his heart” but stressed that Serbian politicians need to be “pragmatic” about the situation.

Following his first-round victory against American Aleksandar Kovacevic, Djokovic wrote “Kosovo is the [heart] of Serbia. Stop the violence” in Serbian on a camera lens, using a heart symbol.

“I believe that Novak Djokovic was saying something from the bottom of his heart. 99% of people Serbian believe in that but I can tell you one thing, that we politicians need to be pragmatic, rational, which means that we need to find solutions through negotiating process, through constructive approach,” the Serbian leader said.

CNN’s Sophie Tanno, Radina Gigova, Josh Pennington, Eve Brennan and Alex Stambaugh contributed reporting.