"Amir Rahimpour, who was the CIA spy and received huge money to give part of the information of Iran's nuclear programme to the intelligence service of America, had already been sentenced to death and it was recently approved by the country's Supreme National court," spokesman Gholam Hossein Esmaili was quoted as saying by Xinhua news agency.
"He (Rahimpour) will be punished soon," the spokesman said, adding that two others have been sentenced to 10 years in prison on charges of spying for the US.
The names of the individuals would not be released yet because the sentence has not been finalized, the spokesman said.
Esmaeeli said that the Supreme Court of Iran has also confirmed the verdict, reports IRNA news agency.
Iran in the past has sentenced alleged American and Israeli spies to death, the Daily Mail said in a report.
The last such spy executed was Shahram Amiri, who defected to the US at the height of Western efforts to thwart Iran's nuclear programme.
When he returned in 2010, he was welcomed with flowers by government leaders and even went on the Iranian talk-show circuit. Then he mysteriously disappeared.
He was hanged in August 2016.
Tensions have escalated between Iran and the US after Iranian Major General Qasem Soleimani was killed in an American drone attack on January 3 in Baghdad.
The attack was ordered by US President Donald Trump, who in May 2018 withdrew the US from the historic nuclear accord Iran had signed with Western powers in 2015.
( With inputs from IANS )