US mother pleads for her jailed son to be released as Iran talks extended

The mother of a former US Marine imprisoned in Iran on espionage charges has pleaded for President Barack Obama to seek his release, as the rival nations seek a historic nuclear deal.

In a letter released just as the United States, Iran and five other powers agreed to extend a temporary deal on Tehran's nuclear program, the mother of Amir Hekmati asked President Obama to take advantage of the cooperative atmosphere to press her son's case.

"This is a historic time for Iran and the United States. I plead that you do not forget... Amir, his service, his beautiful smile and his zeal for life," Behnaz Hekmati, a naturalized US citizen born in Iran, wrote in the letter.

Calling her stress "nearly unbearable," Ms Hekmati said her husband was "gravely ill" with terminal cancer and recently suffered a stroke.

He "wants nothing more than to see his son once again," she wrote.

Iran arrested the US-born former Marine in August 2011, saying that he was trained in Iraq and Afghanistan as a spy. He was sentenced to death, but the penalty was overturned and he was handed a 10-year prison term.

His family denies the espionage allegations, and says that Hekmati, who turns 31 later this month, was merely visiting relatives in Iran.