As Turkish President Recep Tayyip Erdogan prepares to meet his American counterpart Donald Trump in Washington on Tuesday, Turkey's call for the extradition of Fetullah Gulen, leader of the Fetullah Terrorist Organisation (FETO) remains a contentious issue between the two allies.
The extradition will be President Erdogan's top request from the US administration, the response to which can set the tone for relations between the two allies.
Turkey has pressed the US to extradite Gulen, who is accused of orchestrating a defeated coup last July that left 249 people dead and 2,200 others injured.
Ankara has said FETO is also behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary, and has also accused it of infiltrating other countries through educational institutions, among others.
TRT World's Ediz Tiyansan has more on Turkey's most wanted man and FETO from Saylorsburg, Pennsylvania.