The Turkish president, Recep Tayyip Erdoğan, has signed a bill lifting lawmakers’ immunity from prosecution – a constitutional change likely to remove a pro-Kurdish opposition party from parliament.

Erdoğan has accused the pro-Kurdish HDP, parliament’s third-biggest party, of being the political wing of militants who have waged a three-decade insurgency in Turkey’s largely Kurdish south-east. Kurdish militant groups have been blamed for bombings in Turkish cities.

The HDP denies links with militants of the outlawed Kurdistan Workers Party (PKK). It fears an overwhelming majority of its 59 deputies could be jailed under the new law, mostly for views they have expressed.

Lawmakers have until now enjoyed immunity from prosecution. The new law allows prosecutors to pursue any of the 138 members of parliament who are currently under investigation. Of those, 101 are from the HDP or Turkey’s main opposition party CHP.