A US judge has sentenced a banker at Turkey‘s state-controlled Halkbank to 32 months in prison after he was found guilty of taking part in a scheme to help Iran evade US sanctions.

Mehmet Hakan Atilla, a 47-year-old Turkish citizen, was sentenced on Wednesday by District Judge Richard Berman in New York.

The case has strained diplomatic relations between the US and Turkey, and Turkish President Recep Tayyip Erdogan has condemned it as a political attack on his government.

Atilla was found guilty on January 3 of conspiring to violate US sanctions law.

Lawyers for Atilla had sought a sentence of less than four years. US prosecutors wanted 15 years.

They said Atilla, who worked as deputy general manager at Halkbank, was involved in a scheme to help Iran spend oil and gas revenues abroad using fraudulent gold and food transactions through Halkbank, violating US sanctions.

According to prosecutors, the central figure in the scheme was wealthy Turkish-Iranian gold trader Reza Zarrab, who pleaded guilty to fraud, conspiracy and money-laundering charges.

Zarrab, who is yet to be sentenced, testified for several days as the US government’s star witness against Atilla.

On the witness stand, Zarrab said he bribed Turkish officials.

Erdogan has said the US case was based on evidence fabricated by followers of US-based Muslim cleric Fethullah Gulen, whom he has blamed for a failed 2016 coup attempt.

The Turkish president has repeatedly condemned Atilla’s conviction, most recently in an interview with Bloomberg Television on Tuesday.

“If Hakan Atilla is going to be declared a criminal, that would be almost equivalent to declaring the Turkish republic a criminal,” Erdogan said.

Atilla was arrested in New York in March 2017, a year after Zarrab’s arrest in Florida.