Democratic Society Party (DTP) president Nurettin Demirtas was detained around 7:30 pm (1730 GMT) at Ankara's Esenboga airport on his return from Germany, Anatolia said.

The news agency suggested he would likely be placed in police custody.

According to the CNN Turk television channel, 35-year-old Demirtas counts among 185 people under investigation for having avoided military service. All reportedly face between two and five years in prison, if found guilty.

But DTP lawmaker Hamit Geylani, who was at the airport to meet Demirtas, expressed confidence he would be rapidly released.

"There is in no way a situation that could bring about an incarceration," Geylani said.

Demirtas's detention comes a day after Turkish warplanes bombed a number of villages in northern Iraq, targeting what Turkey said were rear-bases of Turkey's separatist Kurdistan Workers' Party (PKK).

Last month, Turkish prosecutors started legal action to ban the DTP, which holds 20 of the parliament's 550 seats and has been accused by Ankara of colluding with the Kurdish rebels.

Elected as party head in November, Demirtas is considered a hardliner within the Kurdish militant movement and was imprisoned during his youth for belonging to the PKK.

The PKK, which is battling for an independent Kurdish state, is considered a terrorist group by Turkey, the European Union and the United States.