German authorities say three people have been arrested in the northern city of Hannover when Kurdish demonstrators protesting Turkish military attacks in northern Syria clashed with police.

The dpa news agency reported that some of the estimated 11,000 protesters threw plastic bottles at police Saturday and threatened them with the flagpoles they were waving.

The demonstrators were also protesting German arms sales to Turkey and chanted slogans like "German tanks out of Kurdistan!" and called Turkish President Recep Tayyip Erdogan a "terrorist."

No incidents were reported at smaller demonstrations in Cologne and Wuppertal.

Some demonstrators waved flags showing the leader of the banned Kurdistan Workers' Party, known as the PKK, and police say they are evaluating videos to see if they can determine their identity.