The Organisation of Islamic Cooperation (OIC) on Wednesday listed a group linked to Turkey's July 15 coup attempt as a terrorist organisation, Foreign Minister Mevlut Cavusoglu confirmed.
"We thank the Organisation of Islamic Cooperation over showing solidarity by understanding our sensitivities and declaring the Gulen group as a terror group," Cavusoglu posted on his Twitter account and described the OIC move as a "milestone".
The OIC's Parliamentary Union, meeting in the Uzbekistan capital Tashkent on Tuesday, denounced all forms of terrorism in a joint declaration.
The body issued a declaration following the meeting expressing its solidarity with Turkey in fighting terror.
Last week, foreign ministers of Gulf Cooperation Council (GCC) member states designated the Gulen group a terrorist group and stressed their support for the Turkish government's recent moves against the network.
Founded in 1969, the OIC, with a current membership of 57 states, is the second-largest inter-governmental organisation after the UN and describes itself as "the collective voice of the Muslim world".
Turkey has been a member since 1969.
Led by Fetullah Gulen, the Gulen group is accused of organising the defeated coup as well as a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.
Turkey has repeatedly asked the US to extradite Fetullah Gulen, who has lived in self-imposed exile in Pennsylvania since 1999.