Turkish authorities detained more than 100 people taking part in an anti-NATO protest march organized by the Communist Party of Turkey (TKP) on Sunday, ahead of an alliance summit in Ankara this week, the party said in a statement.

Turkey will host leaders from the 32 allied countries, as well as officials from NATO's partners, in Ankara for a summit on Tuesday and Wednesday. Authorities have ramped up security measures across the Turkish capital ahead of the meeting, banning demonstrations, barricading large parts of the city, and closing off roads.

In a statement, the TKP said it had organized the protest march in Ankara's central Kizilay square, adding that more than 100 party members, including administrators, had been detained.

Footage showed flag-waving protesters chanting slogans including "Murderer NATO, get out of the country" and "No passage to NATO," as riot police intervened using tear gas to disperse crowds.

In a separate protest organized by the TKP, hundreds of people marched from Istanbul's Taksim Square to Dolmabahce. There were also two separate protests organized by leftist groups in the Kadikoy district. Despite a heavy police presence, there were no scuffles during the protests in Istanbul.

"We have gathered today in many parts of Turkey to protest against NATO," TKP Secretary General Kemal Okuyan said in Istanbul.

"We said that we would not hand over Ankara to supporters of NATO, that we would not allow Ankara to remain silent. We have fulfilled that promise."

The government did not immediately comment on the protests or the detentions.

Near 40 journalists, academics detained in Turkish anti-terror raids

Authorities last month arrested 103 people as part of anti-terror raids in Ankara in which 225 people were detained.

Separately, 39 others, including journalists from independent outlets, activists, and academics, were detained in anti-terror raids across the country, media reported on Sunday.

Tuncer Bakirhan, co-chair of Turkey's pro-Kurdish DEM Party, and main opposition Republican People's Party's (CHP) court-appointed chairman Kemal Kilicdaroglu criticized the detentions as unacceptable measures hindering basic rights ahead of the NATO summit.

"The country has been fully turned into a detention center by using the NATO summit as an excuse," Bakirhan said on X/Twitter. "We are living through days of undeclared martial law."

Turkish prosecutors have previously said the operations were part of efforts to uncover militant group activities, without mentioning the summit.