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 Chavez to intervene with Irans leader, a source close to the release process said on Friday. 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. Venezuelas deputy foreign minister told Reuters on Thursday that Chavez 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 Chavez and he kept on it, the source said. Penns 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 U.S. President George W. Bush, and was involved in humanitarian efforts following Haitis earthquake and Hurricane Katrina. In January, Chavez 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 Chavezs 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. CBN