Turkish President Recep Tayyip Erdogan on Sunday said the tightly-contested referendum on expanding the powers of the head of state was a vote for the future of Turkey.
"We carried out some referendums (in the past) but this referendum is a choice of change and transformation for a new administrative system in the Turkish Republic," he told reporters after casting his vote in an Istanbul school. "God willing, this evening our people will walk to the future by making the expected choice."
Erdogan cast his vote in Uskudar on the Asian side of Istanbul, posing to cameras together with his headscarf-wearing wife Emine, his grandchildren, elder daughter Esra and son-in-law Berat Albayrak, the energy minister.
"First of all, the referendum today is not an ordinary vote," he said.
"I believe our people will, God willing, decide to open the way for a much faster development," he added.
"Because we must make an out-of-the-ordinary choice in order to attain the level of modern civilisations envisaged by the hero Mustafa Kemal," the president said, referring to modern Turkey's founder Mustafa Kemal Ataturk.
Turks are voting Sunday whether to grant Erdogan strengthened executive powers for a change of the parliamentary system into a presidential system.
Critics say the move is part of a grab by Erdogan for one-man rule, but supporters say it will simply put Turkey in line with France and the United States and is needed for efficient government.