BERLIN (AP) - German police said several officers were injured and dozens of people were detained Saturday during unrest at an Eritrean cultural event in the western city of Giessen.

Police said bottles were thrown and smoke bombs were ignited as people tried to tear down barricades around the festival venue.

About 1,000 officers, a water cannon and helicopters are deployed in the city, which is about 50 kilometers (30 miles) north of Frankfurt. Police spokesman Christopher Pfaff urged the public to avoid the center of Giessen while the operation is ongoing.

Authorities had tried to ban the festival after similar unrest linked to political differences within the Eritrean community occurred there last year, but a court overturned the order.

Tens of thousands have fled Eritrea for Europe, many alleging they were mistreated by the autocratic government of Isaias Afwerki.