Erdogan has long accused Gulen, a former ally, of trying to overthrow the government.
Thousands of protesters are out on the streets of Istanbul after the arrest of the city's mayor Ekrem Imamoglu.
Fethullah Gulen's movement has been feared by some for its ability to mobilize considerable resources and for its influence among decision-makers
Erdogan suggested in an interview with Al-Jazeera that coup plotters might still be active in the weeks ahead.
Fethullah Gulen Terrorist Organisation, blamed for last month's failed coup to topple President Tayyip Erdogan in Turkey, has infiltrated" India, according to Turkish Foreign Minister Mevlut Cavusoglu.
Turkish President Recep Tayyip Erdogan's has been trying to mollycoddle India with sweet nothings while having a very close relationship with Pakistan.
Summary of sports events and persons who made news on Sunday
This will be his first visit to India as President.
Turkish President Recep Tayyip Erdogan said the IS extremist group was the "likely perpetrator" of the bomb attack in Gaziantep.
The Manchester and Salford Magistrates' Court heard that the attacker, Karl Anderson, had 25 convictions for 37 offences, including football-related violence, the BBC reported. The 29-year-old will pay a 100 pound ($134) fine.
Prime Minister Narendra Modi and visiting Turkish President Recep Tayyip Erdogan held comprehensive discussions and took stock of full range of bilateral relations, including political and economic.
Turkish President Recep Tayyip Erdogan talks CNN's Becky Anderson.
World leaders are reacting with caution to Donald Trump's jaw-dropping victory in the US presidential election, with some of them reminding him of the democratic values and the global responsibility he carries.
Those killed include 41 police officers, 47 civilians, 2 soldiers, 104 coup plotters.
Summary of sports events and persons who made news on Friday
Indonesia, Turkey and Afghanistan also see important polls in the seven short weeks between end-March and mid-May, says Shankar Acharya