By Parisa Hafezi

UNITED NATIONS (Reuters) - Turkish President Tayyip Erdogan on Tuesday called on world leaders at the United Nations to take measures against a U.S.-based cleric's "terrorist network" that he said threatened their security.

"I am calling, from this podium, to all our friends, to swiftly take the necessary measures against the Gulenist terrorist organization for their own safety and the future of their nations," Erdogan said. 

"It is evident from our experience that if you do not fight the Gulen network at this stage, it may be too late later."

Turkish authorities have accused Fethullah Gulen of orchestrating Turkey's failed coup in July. Gulen, who has lived in self-imposed exile in the U.S. state of Pennsylvania since 1999, has denied involvement in the coup attempt.

Accusing Gulen of building up over decades a network of followers inside the armed forces and civil service to take over Turkey, authorities have asked the United States to extradite or detain the cleric. Gulen denies these charges.

In an interview with Reuters on Monday, Erdogan said the United States should "not harbor a terrorist" like Gulen and said his activities around the world should be banned.

Calling for an immediate political solution to resolve the crisis in Syria, Erdogan said: "Turkey's incursion into northern Syria in early September had led to establishing peace, balance and stability in a region taken over by hopelessness". 

He added: "We cannot lose more time to realize the political resolution process and end the root of the problem, which is the fighting in Syria, terror and atmosphere of cruelty."

Turkey's incursion into Syria came after it had called in vain for several years for world powers to help create a "safe zone" along the Syrian border, with the aim of clearing out Islamic State and Kurdish fighters and of stemming a wave of migration that has caused tension with Europe.

Turkey has said it has no plans to stay in Syria.

"We respect Syria's territorial integrity," Erdogan said.

The president also accused the European Union of not keeping its promises over Turkey's decades-long efforts to join the trading bloc.

(Reporting and writing by Parisa Hafezi; Additional reporting by Tuvan Gumrukcu in Ankara; Editing by Howard Goller and Bill Rigby)