Turkey’s parliament has given preliminary approval to a new constitution which will increase the powers of President Recep Tayyip Erdogan.
There will be a second round of voting later this week and, if approved, a referendum will follow.
Critics claim it amounts to a power-grab by Mr Erdogan.
But the president says the changed system will resemble those in France and the United States.
The new constitution will allow the president to appoint and fire ministers, and it will abolish the post of prime minister for the first time in Turkey’s history.
Instead there will be at least one vice-president.
The bill’s final articles were passed late on Sunday, with the governing AK Party (AKP) gaining the three-fifths majority it needed.
Turkey has been in a state of emergency since a failed coup in July. The status was extended after a series of attacks on the country, including a mass shooting in an Istanbul nightclub on New Year’s Eve.
The constitutional amendments will give the president more scope for declaring an emergency.
Mr Erdogan, 62, came to power in 2002, a year after the AKP’s formation.
He spent 11 years as Turkey’s prime minister before becoming, in 2014, the country’s first directly-elected president – a supposedly ceremonial role.