The US State Department, still mourning the loss of its diplomats in a bloody attack on a mission in Libya, Monday cheered the Oscar win for "Argo" based on a true life tale of diplomatic bravery.

"I think we all were excited to see it win," deputy acting spokesman Patrick Ventrell told journalists of Ben Affleck's film which picked up the coveted best picture award at the Oscars on Sunday night.

The movie tells the story of a CIA operation to spirit six US diplomats out of Iran at the height of the 1979 hostage crisis, when Islamist students took over the US embassy in Tehran holding some 52 people for 444 days.

Although some of the events portrayed in the film have been treated with a large degree of artistic license, the State Department allowed director Affleck's team to film some of the scenes in its main building in Washington.

"We cooperated with them in some of the production aspects of, you know, filming inside of this building," Ventrell said.

New Secretary of State John Kerry on Sunday tweeted ahead of the awards ceremony in Los Angeles wishing "Good luck @BenAffleck and #Argo" and adding "nice seeing @StateDept & our Foreign Service on the big screen - JK."

Affleck, who also stars in the movie, tweeted back his thanks, adding "Grateful for the outstanding service and sacrifice of US diplomats and their families!"

Kerry, who took over earlier this month from Hillary Clinton, has vowed to make the protection of the department's almost 70,000 staff and 275 diplomatic outposts one of his top priorities.

US diplomacy in the world's most volatile regions has been thrust into the spotlight since the September 11 attack on the US mission in Benghazi, Libya in which ambassador Chris Stevens and three other staff were killed.

However, Ventrell had no comment on Iranian charges that the choice of "Argo," which also took awards for best adapted screenplay and best film editing, was political, saying the awards were up to the Academy of Motion Picture Arts and Sciences.

Iran's state television slammed the 85th Academy Awards as "the most political Oscar ever," and accused Affleck of specializing "in exaggeration, blowing things out of proportion and creating false scenes."