ANKARA, Turkey — Turkish troops launched a search Sunday for a lawmaker kidnapped by Kurdish rebels near the eastern city of Tunceli, authorities and the lawmaker’s party said.

Huseyin Aygun, from the main opposition Republican People’s Party, was abducted Sunday evening at a roadblock between the town of Ovacik and Tunceli, party spokesman Haluk Koc said during a televised news conference. A journalist and an adviser traveling with him were set free, he added.

‘‘For the first time, a lawmaker has been kidnapped by the terrorist organization,’’ Koc said. ‘‘It shows where the level of terrorism has reached.’’

The rebels of the Kurdistan Workers’ Party are fighting for autonomy in the Kurdish-dominated southeast region and maintain bases in northern Iraq from where they launch hit-and-run attacks on Turkish targets.

The group is considered a terrorist organization by the United States and the European Union.

Turkey has raised concerns that the rebels could now also exploit a power vacuum in neighboring Syria, and has warned it will ‘‘not tolerate’’ any rebel threats from Syrian territory.

The Turkish government said last month that the rebels have seized control of five towns along the border in collaboration with Syria’s Democratic Union Party — an ethnic Kurdish grouping. Turkey has launched military drills near the frontier in a show of strength.

NTV television reported Governor Mustafa Taskesen of Tunceli Province as saying that Aygun was kidnapped under orders from Kurdish rebel command, which is based deep in northern Iraq.