Turkish voters have endorsed government plans to elect the country's president directly rather than allow parliament to choose, preliminary results suggest.
Abdullah Gul will be Turkey's president until 2014
The High Electoral Board said 69% had approved the constitutional amendments, although turnout for the referendum was low by Turkish standards at 65%.
The reforms were initiated by the AK Party after the opposition blocked the candidacy of President Abdullah Gul.
Mr Gul was eventually elected in August after the AKP's general election win.
The party said the reforms were vital to avoid a re-run of the summer's political deadlock.
It also argued that the new system would be more democratic.
The package of reforms approved on Sunday includes:
- a general election every four years instead of five
- a president elected by direct popular vote
- the president's term lowered from seven years to five
- president allowed to stand for a second term
Opposition parties had urged their supporters to vote "No", saying the reforms would create an overly strong presidency and upset the balance of power.
They said Turkey was in the midst of a much wider constitutional reform process - and that there was no rush as Mr Gul would be president until 2014.
There is also concern that such major changes have not been properly explored since or debated.