NATO chief Jens Stoltenberg has called on Kosovo to ease tensions with Serbia and urged Pristina and Belgrade to engage in the EU-led dialogue.

His response came in a tweet after clashes between Kosovan police and protesters who are opposed to Albanian mayors taking office in ethnic Serbian areas.

NATO chief also spoke to European Union foreign policy Chief Josep Borrell about Kosovo.

Meanwhile, Serbian President Aleksandar Vucic ordered the army to be placed on high alert and start moving towards the border with Kosovo.