TEHRAN — A trial in Iran of an American-Iranian man accused of being a CIA spy has finished and he is now awaiting the verdict, the country's chief prosecutor said Monday, according to the Mehr news agency.

The prosecutor, Gholam Hossein Mohseni Ejeie, also rejected a US government call for the accused man, Amir Mirzai Hekmati, to be released.

The prosecution has demanded the "maximum punishment" in the case, which presumably means the death penalty.

Hekmati, a 28-year-old former US Marine born in the United States to an Iranian immigrant family, was shown on Iranian state television mid-December saying in fluent Farsi and English that he was a CIA operative sent to infiltrate the Iranian intelligence ministry.

In his sole trial hearing, on December 27, prosecutors said Hekmati's "confession" showed he worked with the US Central Intelligence Agency to try to infiltrate the Iranian intelligence ministry by posing as a disaffected former US soldier with classified information to give.

"The trial of the accused is finished. The (defence) lawyer has to submit his argument. The judge has not yet given his verdict," Ejeie was quoted as saying.

He added that the US government was "brazen" to request Hekmati's release, saying he "committed a crime in Iran and must be judged according to the law."

The US State Department said Iran has not permitted diplomats from the Swiss embassy in Tehran -- which handles US interests in the absence of US-Iran ties -- to see Hekmati.

Hekmati, who was born in the United States, travelled to Iran months ago to visit his Iranian grandmothers, according to his family in the US, who insist that he is not a spy.