Polling stations have closed in Turkey's landmark referendum on whether to approve constitutional amendments greatly expanding presidential powers.
Results are expected later Sunday. Turkey has no official exit polls and media are barred from publishing or broadcasting election results until the High Election Board lifts the ban at 1800 GMT or earlier.
If the "yes" vote prevails, the 18 constitutional changes will replace Turkey's parliamentary system of government with a presidential one, abolishing the office of the prime minister and granting sweeping executive powers to President Recep Tayyip Erdoğan.