Supporters of Justice and Development party (AK) wave Turkish flags and hold a poster of Turkish President Recep Tayyip Erdogan outside its offices in Istanbul, Sunday, April 16, 2017.

With 97 percent of the ballots counted in Turkey’s historic referendum, those who back constitutional changes greatly expanding President Recep Tayyip Erdogan’s powers had a narrow lead Sunday night, the official Anadolu news agency said.

The results from Sunday’s vote are expected to have a huge effect on Turkey’s long-term political future and on its relations with the European Union and the world.

Anadolu said 51.4 percent voted “yes” and backed the constitutional changes to replace Turkey’s parliamentary system with a presidential vote, with 48.6 percent voting “no” against them.

More than 55 million people in this country of about 80 million were registered to vote and more than 1.3 million Turkish voters cast their ballots abroad.

Thanking allies

Officials said Erdogan was already thanking allies and supporters for the passage of the constitutional changes as the vote neared its end. Erdogan supporters were celebrating with fireworks in Istanbul as the president said he is “grateful” to the people who “reflected their will.’

However, the vice-chairman of Turkey’s main opposition party said the party will contest 37 percent of the votes counted.

The opposition criticized the decision of the country’s elections board to accept as valid ballot papers that don’t have its official stamp. Republican People’s Party deputy chairman Bulent Tezcan told reporters on Sunday that the decision leaves the results of the constitutional referendum “faced with a serious legitimacy problem.”

Turkey’s Supreme Election Board announced the unprecedented move after many voters casting their votes in the country’s historic referendum complained that they were given ballot papers without the official stamp.

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 the president.

Stability

Erdogan and his supporters say the “Turkish-style” presidential system would bring stability and prosperity in a country rattled by last year’s coup attempt and a series of devastating attacks by the Islamic State group and Kurdish militants.

But opponents fear the changes will lead to autocratic one-man rule, ensuring that the 63-year-old Erdogan, who has been accused of repressing rights and freedoms, could govern until 2029 with few checks and balances.

Erdogan described the referendum as an opportunity for “change and transformation” as he voted Sunday in Istanbul, where black-clad bodyguards with automatic weapons stood guard outside the polling station.

“We need to make a decision that is beyond the ordinary,” Erdogan said.

Kemal Kilicdaroglu, the leader of Turkey’s main opposition party and top “no” campaigner, called the referendum a vote on Turkey’s future.

“We hope the results will be good and together we can have the opportunity to discuss Turkey’s other fundamental problems,” he said.

Turkey’s President Recep Tayyip Erdogan enters a voting booth inside a polling station in Istanbul, Turkey, on Sunday, April 16, 2017