Turkish police have arrested the spokesman of the Peoples’ Democratic Party (HDP) as part of the government’s crackdown on the pro-Kurdish opposition party launched following last year’s failed military coup.

An unidentified Turkish security source said Ayhan Bilgen, who also serves as the MP for the city of Kars, was taken into custody at Ankara Esenboga Airport on Sunday and would be taken to southeastern Diyarbakir Province, Turkey’s Anadolu news agency reported.

Bilgen was detained for his failure to give testimony in an alleged terror probe underway by Diyarbakir prosecutor’s office, the source added.

Huda Kaya and Meral Danis Bestas, two other HDP lawmakers, were arrested on Saturday as part of the same investigation and released under judicial supervision.

The crackdown on opposition is part of measures taken under a state of emergency declared following the abortive military putsch on July 15, 2016, blamed on the movement led by US-based opposition cleric, Fethullah Gulen.

In November 2016, 13 HDP lawmakers were detained on charges of links to Kurdish militants. They have all denied having any ties with the Kurdistan Workers’ Party, also known as the PKK.

Currently, 10 of those arrested, including HDP co-leaders Selahattin Demirtas and Figen Yuksekdag still remain in custody awaiting trial.

Earlier this month, Diyarbakir prosecutors demanded a jail term of between 43 and 142 years for Demirtas and a prison sentence of between 30 and 83 years for the Yuksekdag.

Turkey has banned the PKK as a terrorist organization. The militant group has been calling for an autonomous Kurdish region since 1984.

A shaky ceasefire between Ankara and the PKK that had stood since 2013 was declared null and void by the militants in 2015 in the wake of a Turkish aerial campaign against the group.