Turkish President Recep Tayyip Erdogan narrowly won a historic referendum on Sunday that will tighten his grip on power, but the knife-edge result left the country bitterly divided and the opposition crying foul.

The sweeping constitutional changes approved in the vote create a presidential system that will grant Erdogan more power than any leader since modern Turkey's founder Mustafa Kemal Ataturk and his successor Ismet Inonu.

The result could also have even wider implications for Turkey which joined Nato in 1952 and for the last half-century has set its sights on joining the European Union.

The 'Yes' campaign won 51.4 per cent of the vote against 48.6pc for 'No', the election commission said in figures quoted by state news agency Anadolu, in a count based on 99.5pc of the ballot boxes. Turnout was a high 85pc.

As huge crowds of flag-waving supporters celebrated on the streets, Erdogan praised Turkey for taking a “historic decision”.

“With the people, we have realised the most important reform in our history,” he added.

But opposition supporters in anti-Erdogan districts of Istanbul showed their dissatisfaction by bashing pots and pans with kitchen utensils to create a noisy protest. Hundreds also took to the streets in the areas of Besiktas and Kadikoy.

Supreme Election Board chief Sadi Guven confirmed that the 'Yes' camp had emerged victorious, but the opposition has vowed to challenge the outcome.

'New page opened'

The referendum was held under a state of emergency that has seen 47,000 people arrested in an unprecedented crackdown after a failed military putsch against Erdogan in July last year.

In a nail-biting end to a frenetic campaign, the 'No' share of the vote climbed as more ballots were counted, after lagging well behind in the early count, but failed to overtake the 'Yes' votes.

“This is a decision made by the people. In our democracy's history, a new page has opened,” said Prime Minister Binali Yildirim, whose job will disappear under the constitutional changes.

In a television interview on Friday Erdogan had predicted a far clearer victory saying polls showed a 55-60 percent share of the vote.

But voting patterns showed Turkey deeply divided over the changes, with the 'No' vote victorious in the country's three biggest cities.

The 'Yes' vote held up strongly in Erdogan's Anatolian heartland but the Aegean and Mediterranean coastal regions and Kurdish-dominated southeast backed the 'No' camp.

In a major disappointment for the president, the 'No' vote was just ahead in his hometown of Istanbul and in the capital Ankara and clearly ahead in the third city of Izmir.

A statement issued by European Commission head Jean-Claude Juncker and EU foreign affairs chief Federica Mogherini said that in view of the closeness of the result, the Turkish authorities need to seek the “broadest possible national consensus” for the changes.

Erdogan made relations with the EU a key issue in his referendum campaign, lambasting Brussels for failing to make progress on Ankara's stalled accession talks and he accused Germany and the Netherlands of acting like the Nazis when they barred pro-government rallies. -AFP