Turkish Prime Minister Binali Yildirim and opposition Nationalist Movement Party (MHP) leader Devlet Bahceli met on late Monday to discuss a new draft constitution, a prime ministry source said.
According to the source, who spoke on condition of anonymity due to restrictions on talking to the media, the two leaders came together at the Cankaya Palace in Ankara.
The source said that Yildirim and Bahceli exchanged views on the fight against terrorism during the meeting.
The government has long sought to replace the current parliamentary system with a presidential one, saying there are flaws in the setup which hold back Turkey's development.
However, the ruling Justice and Development (AK) Party does not have enough lawmakers alone to enact the proposal. The draft constitution needs at least 330 votes in a secret parliamentary ballot to pave the way for a referendum.
The AK Party has 316 seats while the MHP has 40 lawmakers; both parties back the bill.
The largest opposition group, the Republican People's Party (CHP) remains opposed to the changes.
President Recep Tayyip Erdogan emphasized that he will push for a referendum even if the draft is approved by a two-thirds majority in parliament.
Anadolu Agency