ROME, Sept 23 (Reuters) - A U.S.-based Turkish cleric accused by Tayyip Erdogan of treason said the President was using a failed coup to promote himself as a national hero and urged Europe to intervene to prevent "catastrophe" as purges from the army to the judiciary proceed.
Fethullah Gulen, who denies backing the July putsch, suggested in an interview with Italian daily La Stampa Europe's leaders had done too little in criticizing Erdogan over the arrest of tens of thousands, from the army and journalism to the judiciary and arts, and the suspension of some 100,000 people.
"Internal pressure from refugees, the proliferation of radical groups, the persecution of tens of thousands of civilians, Erdogan's rash self-proclamation as national hero... should compel European leaders to take effective action to stop the...government's move towards authoritarianism," he said.
He did not say what form such action might take.
Erdogan has long been by far the most popular politician in Turkey - a popularity critics say he has abused to extend his powers and clamp down on dissent. After the failed coup his popularity rose still further.
Turkey hosts nearly three million refugees from war in Syria. Implementing a deal the EU struck with Turkey to stem the flow of illegal migrants to Europe has been delayed by disputes over Turkey's anti-terrorism laws and the post-coup crackdown.
"Reinforcing democracy, the rule of law and respect for human rights in Turkey is absolutely necessary to manage the refugee crisis and the fight against (Islamic State) in the long term. If this doesn't happen, Europe risks finding itself with an even bigger problem, a catastrophe," Gulen said.
Gulen was once a close ally of Erdogan, but the relationship has become openly hostile in recent years, culminating in Erdogan accusing Gulen of orchestrating the July coup.
More than 240 people were killed in the July 15 coup. Gulen denies any involvement and has condemned it.
Gulen said European leaders should encourage Turkey's entry into the European Union - another element of the refugee deal - as it could strengthen democracy and respect for human rights. (Reporting by Isla Binnie; editing by Ralph Boulton)