BERLIN — German police broke up a protest rally of more than 20,000 Kurdish immigrants after participants refused to take down flags and symbols of the banned Kurdistan Workers’ Party, German news agency dpa reported Saturday.

The demonstrators had come to the western city of Cologne from all over Germany to protest Turkey’s recent military operation in a Kurdish enclave in northern Syria.

“The protest march has been stopped in order to remove all forbidden banners,” police of the state of North Rhine-Westphalia tweeted Saturday afternoon.

Despite repeated demands from police, many people at the march continued waving flags bearing an image of Kurdistan Workers’ Party leader Abdullah Ocalan, who is imprisoned in Turkey.

Two people who distributed flags were detained, dpa reported.

The Kurdistan Workers’ Party, also known by its Kurdish acronym PKK, is regarded as a terror group by Turkey and its Western allies. The group has waged an insurgency against the Turkish state for three decades.

Hostilities between Turkey and Kurdish militants resumed in 2015 after a fragile cease-fire collapsed.

After police terminated the Cologne protest march, they reported scuffles between demonstrators and officers in front of the city’s train station. Officers fired tear gas after a protester allegedly threw a flag at police. There was no information immediately available about possible injuries, dpa reported.

Clashes between Kurdish and Turkish immigrants who back the Syrian military operation ordered by Turkish President Recep Tayyip Erdogan did not materialize, as Cologne police had feared.

Turkish troops and allied Syrian fighters started operations last week against the Kurdish-held enclave of Afrin, approaching from three sides and meeting stiff resistance from the U.S.-allied Kurdish militia that controls the area. Turkey says it is fighting extremists threatening regional stability.

Several thousand people in Paris also protested the Turkish operation Saturday.

Left-wing activists joined Kurdish opposition groups in the demonstration at the Place de la Republique in the east of the French capital.

The demonstrators urged French and other Western authorities to take a tougher stand against the Turkish campaign. France’s government has urged Turkey to use restraint, but the protesters said that was not enough.