In recent weeks, Serbs in northern Kosovo have responded with violent resistance to moves by Pristina that they see as anti-Serb.

“I know the two parts are willing to de-escalate and I strongly call on the two of them to do it,” Josep Borrell said as he arrived at a meeting of EU foreign ministers.

“They have to come back to the dialogue. They have to overcome this tendency of fighting in the street.”

The latest protests were triggered by the arrest of a former police officer on Saturday.

He was part of a mass resignation of Serbs from the force last month, after Pristina said it would require Serbs to scrap Serbian licence plates dating to before the 1998-99 Kosovo War that led to independence.

For a second day on Sunday, trucks and other heavy-duty vehicles blocked several main roads leading to two border crossings with Serbia. Both crossings were closed to traffic.

Eulex, the EU mission tasked with patrolling northern Kosovo, said a stun grenade was thrown on one of its armoured vehicles on Saturday evening, but no one was injured.

Borrell said that was unacceptable.