A former premier and ex-ally of President Recep Tayyip Erdogan launched a new party on Friday, saying it would stand against "cult of the leader" politics.
Ahmet Davutoglu, who served as prime minister between 2014 to 2016 and chairman of Erdogan's ruling party, formally presented the Future Party ("Gelecek Partisi" in Turkish) at a ceremony in Ankara.
"As a party, we reject a style of politics where there is a cult of the leader and passive personnel," Davutoglu said, standing beneath a large banner featuring the revered founder of the Turkish republic, Mustafa Kemal Ataturk.
Davutoglu, 60, did not mention Erdogan by name during his nearly one hour speech, but criticised the sweeping powers given to the presidency under constitutional changes last year.
"It won't be possible to have a democratic society with the system continuing like this," said Davutoglu, who resigned from the ruling Justice and Development Party (AKP) in September.
Analysts say Davutoglu is seeking to peel away conservative Muslim voters from the ruling AKP, and while few expect him to attract more than a fraction of the electorate, it could be enough to cause problems for Erdogan.
Davutoglu insisted his party would stand for minority rights, the rule of law, freedom of the press and an independent judiciary -- in a swipe at the deterioration of civil rights during Erdogan's 16-year rule.
Once a close ally of Erdogan, the two men fell out over a number of issues, most notably the changes to the constitution, and he was forced to resign as premier in May 2016.
He is not the only former Erdogan ally challenging the president. Ex-economy minister, Ali Babacan, is expected to launch his party later this month.
Davutoglu previously served as foreign minister during a particularly rocky period in Turkey's international relations in the early 2010s.
He has been fiercely criticised as the architect of Ankara's efforts to take a more assertive stance across the Middle East -- backing the Muslim Brotherhood and its allies in several countries, and supporting rebels in Syria -- which ultimately left Turkey with few friends in the region.