Turkey’s Prime Minister Ahmet Davutoglu says he will stand down at an extraordinary congress of his ruling AK Party later this month.
Speculation about his resignation has been rife since Mr Davutoglu met President Recep Tayyip Erdogan on Wednesday.
He is long thought to have disapproved of Mr Erdogan’s plans to move Turkey to a presidential system of government.
He announced his resignation after holding talks with party leaders.
The congress would be held on 22 May, he said.
Earlier on Thursday, presidential aide Cemil Ertem said there would be no snap elections following the appointment of a new leader.
He also told Turkish TV that the country and its economy would stabilise further “when a prime minister more closely aligned with President Erdogan takes office”.
Why is this happening now?
After he was elected president in 2014, Mr Erdogan hand-picked Mr Davutoglu to succeed him as head of the AK Party (Justice and Development Party).
But the prime minister’s unease with Mr Erdogan’s plans to move to a presidential system, among other policies, has been evident in recent months.
In a sign of his weakening influence, Mr Davutoglu was stripped last week of the authority to appoint provincial AK Party officials.
What will this mean for Turkey?
The development comes at a time of increasing instability for Turkey, which is tackling an escalating conflict with the rebels of the Kurdistan Workers’ Party (PKK), attacks by the so-called Islamic State, and an influx of migrants and refugees.
Turkey is also in the midst of implementing a key deal with the European Union, brokered by Mr Davutoglu, to limit the number of refugees flowing across its border in return for accelerated EU accession talks and financial aid.
The future of that agreement, which Mr Davutoglu was seen as having agreed with little input from the president, could be plunged into doubt by his departure.
Who will be his successor?
Among those tipped as successors to Mr Davutoglu are Transport Minister Binali Yildirim, who is close to Mr Erdogan, and Energy Minister Berat Albayrak, who is the president’s son-in-law.
They will be formally elected at the party congress.
What has been the fall-out?
The political uncertainty has rattled the financial markets. The Turkish lira suffered its heaviest daily loss on Wednesday, down almost 4% against the US dollar. It rallied slightly on Thursday but was still well off its previous trading levels.