Iran hanged on Monday two activists it said were members of an exiled group and who had joined protests against the result of the 2009 presidential poll, despite Washington urging that they be freed.
The executions were the first reported hangings of protesters who took to the streets in their thousands following the re-election of President Mahmoud Ahmadinejad in a June 2009 election they said was rigged.
The Tehran prosecutor's office named the pair as Jafar Kazemi and Mohammad Ali Hajaghaei. It did not say where they were hanged.
"Two elements of the Monafeghin (hypocrites) group named Jafar Kazemi... and Mohammad Ali Hajaghaei ... were executed early today," the prosecutor's office said on its website, referring to the Iranian exiled opposition group, People's Mujahedeen of Iran (PMOI).
On August 10, US Secretary of State Hillary Clinton had urged the Iranian authorities to release the two activists, despite the PMOI being on Washington's list of foreign terrorist organisations.
The prosecutor's office said "these two hypocrites were members of an active network of the said group and were involved in the (post-election) riots under the guidance of their ringleader in England."
"The convicts had resorted to distributing pictures and banners related to the Monafeghins, taking photos and films of the clashes as well as chanting slogans in favour of the group."
The 2009 presidential election result triggered widespread anti-government demonstrations in Tehran and some other cities.
Dozens of protesters were killed, scores wounded and thousands jailed when security forces clashed with them after the announcement of the election result, which Ahmadinejad's rivals claim was rigged in his favour.
Clinton had urged that those rounded up, including Kazemi and Hajaghaei, be freed.
"We are also concerned about the fate of Iranians who are in danger of imminent execution for exercising their right to free expression after the June 2009 elections," Clinton said on August 10 in a statement, naming Kazemi and Hajaghaei.
Her plea for the release of the two activists came despite Washington retaining the PMOI on its list of foreign terrorist organisations, even as the European Union took it off its own similar list in 2009.
The prosecutor's office said Hajaghaei had a history of travelling to Iraq, where the PMOI's main camp is based.
"While staying there for a few months, he received 3,000 dollars and training sessions from the Monafeghins in Camp Ashraf," the office said, referring to the PMOI camp located in the Iraqi province of Diyala.
It said the other condemned man, Kazemi, had confessed to his activities during the post-election unrest.
"Kazemi admitted putting up pictures supporting members of the terrorist Monafeghin group as well as filming the street protests in Azadi (Freedom) Square and Enqelab (Revolution) Street" in Tehran, it said, referring to venues where bulk of brutal post-election unrest occurred.
Kazemi also confessed to having interviewed families of some of the members of Camp Ashraf, it added.
Iran has sentenced around a dozen activists to death for their role in the post-poll unrest. Six of the sentences have been upheld by Tehran prosecutor Abbas Jafar Dolatabadi, with the hangings on Monday the first carried out.
The six are all said by the authorities to be members of PMOI, including the two hanged on Monday. Dolatabadi said in May that Kazemi and Hajaghaei were arrested in September 2009.
The PMOI is responsible for several acts of violence against Iranian civilians and government officials.
It is also known to have participated with former Iraqi dictator Saddam Hussein's forces during their war with Iran in the 80s.
The members of Camp Ashraf were disarmed after the 2003 invasion of Iraq by US-led forces.