Turkish Justice Minister Bekir Bozdag says the arrest of Halkbank's Mehmet Hakan Atilla in the US is aimed at "tarnishing" Turkey and its leaders. Turkey is also discussing the issue with visiting US Secretary of State Rex Tillerson in Ankara.
The arrest in the United States of a top Turkish banker charged with participating in a multi-year scheme to violate sanctions against Iran is a "completely political" move, Turkish Justice Minister Bekir Bozdag said on Thursday.
Mehmet Hakan Atilla, a deputy chief executive officer of Halkbank, is accused of conspiring with Turkish-Iranian gold trader Reza Zarrab, who is already on trial.
Bozdag said there is no evidence incriminating Zarrab or Turkey.
The arrest escalates a case that has fuelled tension between Turkey and the US.
President Recep Tayyip Erdogan said he believed US authorities had "ulterior motives" in prosecuting Zarrab, who was arrested in March 2016, in Miami.
Atilla is accused of conspiring with Zarrab to conduct hundreds of millions of dollars of illegal transactions through US banks on behalf of Iran's government and other entities in that country.
The Turkish president and senior officials are expected to raise Atilla's arrest with visiting US Secretary of State Rex Tillerson, who arrived in Ankara on Thursday as the US is looking to improves its relations with NATO ally Turkey.
Tillerson is the most senior American official to visit Turkey since the inauguration of Donald Trump as US president in January.