The US President Barack Obama and German Foreign Minister Guido Westerwelle have issued statements commending the vote.

Voters in Turkey gave strong backing to a package of changes to the country's military-era constitution.

The changes are aimed at bringing Turkey in line with the European Union, which the government wants to join.

With nearly all votes in the referendum counted, about 58% had voted "Yes" to amending the constitution.

Prime Minster Recep Tayyip Erdogan said the result meant the country had "crossed a historic threshold toward advanced democracy and the supremacy of law".

The opposition argues that the governing party, which has its roots in political Islam, is seeking dangerous levels of control over the judiciary.