Iran’s Supreme Court ordered a retrial for an Iranian American former Marine who initially was sentenced to death for spying. (Anonymous/AP)

Iran’s Supreme Court ordered a retrial for a former U.S. Marine who was sentenced to death on spying charges, the country’s national prosecutor said Monday.

Amir Mirzaei Hekmati, 28, an Iranian American who was sentenced in January to be hanged, waited more than a month for the Supreme Court to decide whether he would be the first U.S. citizen to get the death penalty in Iran since the 1979 Islamic revolution.

Born in Arizona, Hekmati served in the Marine Corps from 2001 to 2005 and fought in Iraq in 2004. He later worked as a contract translator in Afghanistan. He holds an Iranian passport as well as an American one.

His Iranian attorney, Mohammad Hossein Aghassi, had pleaded with U.S. authorities to do everything in their power to prevent an execution — including a swap of Iranian prisoners held in the United States.

The semiofficial Iranian Students’ News Agency reported Monday that the case would be retried.

“There was an appeal on his verdict,” chief government prosecutor Gholam Hossein Mohseni-Ejei told a news conference. “The Supreme Court found shortcomings in the case and sent it for review by an equivalent branch” of the court system.

Aghassi said that the Supreme Court referred Hekmati’s case back to the court that handed down his death sentence.

“We hope that now his death sentence will be overturned,” Aghassi said. “It doesn’t seem that any deal has been made with the U.S.”

In Washington, State Department spokeswoman Victoria ­Nuland said that news of the retrial was “a welcome development,” and she expressed hope that Hekmati “will be reunited with his family soon.”

Nuland added: “We have, regrettably, still not been able to have contact with him” through the Swiss Embassy in Tehran, which represents U.S. interests in Iran. She said this was because Iranian authorities do not recognize Hekmati’s U.S. citizenship.

Precisely when and where Hekmati was arrested remain unclear. Iranian news reports have said that Hekmati was ­detained in late August or early September on arrival in Iran. His family members, who live in Michigan, have said that he was in Iran to visit his grandmother.

Hekmati appeared on Iranian state television in December and purportedly confessed to working for the CIA. It is unclear whether the statements were made under duress.

“It was their plan to first burn some useful information, give it to them [the Iranians] and let the Intelligence Ministry think that this is good material and contact me afterwards,” Hekmati said in his television appearance.

He went on to say that the CIA ordered him “to become a source for [Iran’s] Intelligence Ministry” and remain in Tehran “for three weeks and feed them this information, get some money for it and come back.”

U.S. officials have denied that Hekmati is a spy. Iran considers Hekmati an Iranian, not an American, because it does not recognize dual citizenship.

The assassination of several Iranian nuclear scientists and mysterious explosions at military and industrial sites in Iran in recent years have prompted Tehran to keep closer tabs on dual nationals visiting the country.

Hekmati was convicted of working with a hostile country, belonging to the CIA and trying to accuse Iran of involvement in terrorism, the Fars News Agency reported.

The court described him as a “mohareb,” an Islamic legal term meaning that he “waged war against God,” and a “mofsed,” or someone who “spreads corruption on the earth.” The judge, Abolghassem Salavati, has presided over mass trials against activists, sentencing at least three people to death after similarly labeling them.

Hekmati’s mother traveled to Iran in February and visited her son three times in Tehran’s Evin prison.

“There is still a possibility of him being executed,” Aghassi said. “But our hopes are up now.”

In a separate political development, Iran’s interior minister on Monday announced a second round of parliamentary elections in April in several key cities, including the capital, after candidates in a number of constituencies failed to reach the vote threshold to be elected.

Under the Iranian electoral system, a candidate must receive at least 25 percent of the vote to be elected.

In Tehran, the largest constituency in Iran, only five out of 30 pre-selected candidates received enough votes. Several seats in large cities such as Mashhad, Shiraz and Abadan also remained undecided. A date for the second round has not been set.

Interior Minister Mostafa ­Najjar announced during a news conference that 225 candidates have been elected. At stake as voters went to the polls Friday were all 290 seats in the Majlis, or parliament.

While Najjar did not comment on the winners, the majority are individuals who support Iran’s leaders. Analysts said that they are likely — for now — to criticize President Mahmoud Ahmadinejad but not impeach him.