Turkish Foreign Minister Mevlüt Çavuşoğlu spoke to Attorney General Jeff Sessions on Tuesday about the possible extradition of the man held responsible for last July's attempted coup.
Çavuşoğlu presented Sessions with a dossier including new evidence to support Ankara's request to extradite Fetullah Gulen, a Turkish official said on condition of anonymity due to restrictions on speaking to the media.
The foreign minister visited Sessions during a two-day trip to Washington.
Separately, Turkish Justice Minister also spoke to Sessions about the extradition request during a telephone call lasting nearly 30 minutes.
Turkey has stepped up its efforts to have Gülen, the leader of the Fetullah Terrorist Organization, since the coup bid, in which 249 people died.