At least 25 members of the international force in Kosovo were wounded on Monday. Protesters were demanding the departure of Albanian mayors.
The majority of Serbs in the north of the country do not recognize Pristina's authority. Some 120,000 Serbs live in Kosovo, about one third of them in the northern part of the territory. The attacks were described as "totally unacceptable" by NATO in Brussels, which ordered the army to be on high alert in the region. The incident follows a series of clashes between police and protesters in recent weeks.