The US has arrested a senior official at a state-owned Turkish bank on charges of helping Iran violate US sanctions, a move that could fuel tension ahead of Secretary of State Rex Tillerson's visit on Thursday.
Halkbank's Mehmet Hakan Atilla is accused of helping to process millions of dollars of illegal transactions through US banks for the Iranian government and other Iranian institutions, the state-run Anadolu news agency reported.
"Our deputy general manager in charge of international banking, Mehmet Hakan Atilla, was taken into custody in the United States where he was for business purposes on March 28," the bank said, adding that it was working with the authorities.
Confirmation of the arrest hit the bank's shares hard Wednesday morning, sending them down 14 percent to 10.36 lira ($2.84; 2.63 euros) at 0905 GMT.
Anadolu said Atilla was accused of two crimes when he appeared before a judge in New York on Tuesday: conspiring to violate US sanctions against Iran and banking fraud.
It said Atilla faced up to 50 years in prison.
The arrest came ahead of Tillerson's meeting on Thursday with Turkish leaders, including President Recep Tayyip Erdogan and Foreign Minister Mevlut Cavusoglu.
Speaking to the private NTV television late on Wednesday, Prime Minister Binali Yildirim said the case would be discussed during Tillerson's visit.
"(We are) going to bring the issue up and certainly ask for the reasons behind this," he said.
"We will closely monitor the legal process."
Cavusoglu said Turkey would bring to the agenda "our worries" over the detention during the key visit.
The talks would also focus on the Syria conflict, now in its seventh year, and the requested extradition of US-based preacher Fethullah Gulen, whom Ankara accuses of ordering a failed coup last year, he told the state-run TRT television.
Gulen has denied the charges, but Ankara has repeatedly called on Washington to return him to Turkey.
- Links to detained executive? -
Atilla is accused of working with Reza Zarrab, an Iranian-Turkish businessman, and others to let the Iranian government and other Iranian institutions get around US sanctions.
Zarrab, 33, was arrested in Miami in March last year en route to Disney World on charges that could see him sentenced to up to 30 years in prison.
His arrest stunned Turkey, where Zarrab had been linked to a 2013 corruption scandal that had ensnared the government at a time when Erdogan was prime minister.
The scandal broke on December 17, 2013, when the sons of former Turkish ministers were detained by police, as well as pro-government figures including Suleyman Aslan, then the CEO of Halkbank. All were subsequently released.
Zarrab had spent 70 days in custody in Turkey over the scandal, which Erdogan denounced as a plot by Gulen to bring down his government.
The American charges against Zarrab include conspiring to violate US sanctions against Iran, defraud US banks and launder money by helping Iranian entities transfer funds through US institutions.
Atilla is to appear again in court on April 10, Anadolu said, adding that he would remain in jail.