Turkish leaders on Tuesday stepped up their calls for the United States to punish Fethullah Gulen, the reclusive cleric living in Pennsylvania whose organization is said to be behind the failed July 15 coup attempt that sought to topple President Recep Tayyip Erdogan and his government.

Officials in Ankara insist that Gulen had a direct hand in the coup plot, a mutiny led by a faction in the military that led to about 290 deaths before it was quashed.

U.S. Secretary of State John F. Kerry said he would consider an extradition request should Turkey submit “legitimate evidence [of Gulen’s involvement] that withstands scrutiny.”

His Turkish counterpart, Foreign Minister Mevlut Cavusoglu, said the United States needs to take Turkey’s concerns seriously.