Turkish President Recep Tayyip Erdogan said Thursday he would meet US counterpart Donald Trump in May, a month after he won a contested referendum that will tighten his grip on power.

The US meeting -- the first since Trump took office -- will be a key chance for Erdogan to build a strong alliance with Trump as Ankara's relationship with the European Union goes through one of its worst ever crises.

"The date has been fixed," Erdogan told A News in an interview, saying the trip would happen after he concludes a visit to China on May 15.

"I hope and pray that this tete-a-tete meeting in the United States in May will lay the foundation for a stronger cooperation."

The announcement came after Trump surprised many observers by phoning the Turkish leader to congratulate him for winning a controversial weekend referendum on enhancing his powers.

Russian President Vladimir Putin called his Turkish counterpart to offer congratulations.

The 'Yes' camp won Sunday's poll with just 51.41 percent of the vote but the result has been challenged, with the opposition claiming the vote was rigged and angry protests erupting in parts of Istanbul.

The European Union has also urged a probe into fraud claims after international observers voiced concerns.

In the last few months of Barack Obama's presidency, relations between the NATO allies hit a rough patch with Turkey furious over US backing for a Kurdish militia in Syria it sees as a terror group.

Ankara is also pressing Washington to extradite Fethullah Gulen, the US-based Islamic preacher it accuses of being behind last year's failed coup. Gulen denies the charges.

Asked about his potential future relationship with Trump, Erdogan said: "It's very early to comment. When I met president Obama for first time I was very hopeful. Let's embark on this journey."

But he appeared upbeat about the prospects, saying the two had already spoken three times by phone. "Every time we spoke to one another, I have become more hopeful."

He also said that Trump's background as a successful businessman was a help.

"We have an advantage. President Trump is a very successful businessman, he is tycoon in real estate, he was a brand."

He also expressed confidence that Washington would extradite Gulen, saying: "I believe president Trump will do what president Obama failed to do."

Indicating that major meetings with EU leaders were not currently on the agenda, Erdogan said his schedule for trips after the referendum also included Russia and India.

Turkish media said a meeting with Putin would be held on May 3.

Turkey's election authority on Wednesday rejected opposition requests to cancel the referendum result. The main opposition Republican People's Party (CHP) had claimed major ballot rigging swung the result.

But Erdogan mocked CHP suggestions that it would now ask Turkey's Constitutional Court or the European Court of Human Rights to cancel the referendum.

As for the Constitutional Court, "this is not part of its jurisdiction" while the European judicial instance "does not have a mandate this is a domestic affair," said Erdogan.

Addressing the CHP, he said: "You will not get anything out of this. The Supreme Election Board made its decisions. This is the will of the people."

With Turkish police beginning to crack down on those who have called for demonstrations over the result, left-wing website sendika.org said its editor-in-chief Ali Ergin Demirhan was held in a pre-down raid on its offices.

The arrest comes after at least 16 leftist activists involved in demonstrations against the 'Yes' victory were detained by Istanbul police on Wednesday. In all, a total of 38 arrest warrants were issued.

The opposition is particularly incensed by a last-minute move by the election authorities to accept ballot documents in envelopes without an official stamp.

Source: Ahram online