SKOPJE, Macedonia (AP) — Authorities in Macedonia say police have clashed with an armed group in the northern town of Kumanovo, and parts of the town have been sealed off.

Macedonia's state-run news agency MIA reported that four police officers were injured by gunfire, and three of them were taken to a hospital the capital, Skopje.

Interior ministry spokesman Ivo Kotevski said the police operation information that an armed group is operating in the region of Kumanovo, a 50 kilometers (30 miles) north of Skopje.

Kotevski offered no more details about the group targeted by the police operation.

The incident came a day after thousands of opposition supporters joined nationwide protests against alleged police brutality.