President Recep Tayyip Erdogan gave his approval Tuesday to legislation that will strip the legal immunity of more than 130 parliament members, in a move widely seen as targeting pro-Kurdish lawmakers.
Erdogan's approval, reported by broadcaster NTV and other outlets, is needed for the bill, which has the power of constitutional amendment, to become law and paving the way to prosecutions.
A two-thirds majority in parliament approved the measure last month.
The United States and the European Union have expressed concerns over the immunity bill.
The measure was widely seen as targeting the pro-Kurdish Peoples' Democratic Party (HDP), as more than 50 of their 59 members in the 550-seat house would be affected. However, the bill could have implications for all four parties in the legislative house.
Turkey's Constitutional Court last week rejected an appeal against the legislation by lawmakers from the HDP and some from the centre-left Republican People's Party (CHP), which is split over the matter.
The far-right Nationalist Movement Party (MHP) has largely backed the immunity bill, which was initiated by the ruling Justice and Development Party (AKP). The AKP's key founder, Erdogan, has repeatedly called for HDP members to lose their legal protection.
Erdogan has alleged tight connections between the HDP and the banned Kurdistan Workers' Party (PKK), something the legal party denies.