Sean Penn worked to get Americans from Iran

US actor Sean Penn engaged in attempts to secure the release of two Americans freed by Iran this week, flying to Venezuela to ask President Hugo Chávez to intervene with Iran's leader, a source close to the release process said.

Since Tehran freed Josh Fattal and Shane Bauer on Wednesday details have emerged about the efforts to win their freedom, which involved the United Nations, Iraq and Oman -- as well as Chavez, who is a fiery critic of the United States.

Venezuela's deputy foreign minister told reporters on Thursday that Chávez brought up the case with his Iranian ally Mahmoud Ahmadinejad after being alerted to the Americans' plight by friends in US "intellectual circles."

"The American 'intellectual' who took up the case with him was Sean Penn," the source told Reuters.

"Penn was very committed to the case ... He flew to Caracas several months ago to raise it with Chávez and he kept on it," the source said.

Penn's spokeswoman in the United States confirmed this account, but would give no further details.

The two Americans had been in Iranian custody since their arrest in July 2009 on the border with Iraq, where they said they were hiking. They were jailed for espionage.

Penn, known for his political and social activism, won best actor Oscars for his roles in the Clint Eastwood-directed drama "Mystic River" in 2003 and as slain gay politician Harvey Milk in the 2008 movie "Milk."

The actor, screenwriter and film director was sharply critical of the administration of former US President George W. Bush, and was involved in humanitarian efforts following Haiti's earthquake and Hurricane Katrina.

In January, Chávez joked that Washington should end a diplomatic stand-off with Caracas by appointing either Penn, Bill Clinton or director Oliver Stone as its next ambassador to Venezuela. "We have a lot of friends there," Chavez said.

The source said the State Department had been aware of Chavez's involvement in the attempts to free the hikers and did not try to block it. On Thursday, a State Department spokesman said only that they were happy Fattal and Bauer were safe.