Iranian state media is reporting that the Supreme Court has overturned a death sentence for a dual U.S.-Iranian citizen convicted of spying for the CIA.

Quoting the prosecutor general, ISNA reported on Monday that the case of former U.S. Marine Amir Mirza Hekmati “has been sent back” to a lower court for retrial.

Iran's Revolutionary Court announced in January that Hekmati was convicted of several crimes — including cooperating with a hostile nation, being a member of the CIA and trying to implicate Iran in terrorism.

The 28-year-old Hekmati was arrested in December.

Iranian TV showed Hekmati in December appearing to confess his crimes, in a mixture of English and Farsi. Hekmati said he was an American CIA operative sent to infiltrate the Iranian intelligence ministry. He talked of receiving language and espionage training.

The White House has denied that Hekmati was a spy and has been demanding his immediate release.

Hekmati said he received the training at U.S. bases in Iraq and Afghanistan before traveling to Iran to carry out his alleged espionage. His family said he was in Iran visiting grandparents.

It added to deteriorating relations between Iran and the West that are growing increasingly tense over Iran's controversial nuclear program. Washington and Israel fear Iran is pursuing an atomic weapons program. Tehran says its nuclear ambitions are peaceful.