Turkey has rejected as "ludicrous" allegations that it offered several million dollars to the United States to extradite a political rival to president Recep Tayyip Erdogan.
US media reported that investigators in Washington are probing whether former White House national security adviser Michael Flynn discussed expelling Muslim preacher Fethullah Gulen in exchange for a secret payout.
Ankara blames Mr Gulen's movement for the July 15, 2016 failed coup against Mr Erdogan, and has pressed for his extradition from the United States, where he has lived since 1999.
Mr Gulen, who has a large Turkish following, strongly denies the charges.
"All allegations that Turkey would resort to means external to the rule of law for his extradition are utterly false, ludicrous and groundless", Turkey's embassy in Washington said on Twitter Saturday.
NBC News and the Wall Street Journal said Friday that US special prosecutor Robert Mueller is examining a meeting Mr Flynn had with senior Turkish officials weeks after Donald Trump won the presidential race last year.
The meeting allegedly discussed a secret payout of up to $15 million dollars if, once in office, Mr Flynn would engineer the deportation to Turkey of Mr Gulen as well as help free Erdogan-linked Iranian-Turkish businessman Reza Zarrab from prison.
NBC and the Journal both cited multiple people familiar with the probe by Mr Mueller, who is leading the investigation into whether members of Mr Trump's campaign colluded with Russian meddling in the election.
The Journal said it is not clear how far the proposal went and that there was no sign that any payments were made.
Lawyers for Mr Flynn have labelled the allegations "outrageous" and "false".
According to the two reports, the discussions included details of how Mr Gulen could be flown secretly by private jet to the isolated Turkish prison island of Imrali.
