More than a week after he admonished a reporter who asked why he was "content" that the freedom of US prisoners in Iran was not secured in the nuclear deal with Iran, US President Barack Obama finally called for the release of the detainees.

Obama named the American detainees one by one during his speech at the Veterans of Foreign Wars convention on Tuesday, Fox News wrote.

"We are not going to relent until we bring home Americans who are unjustly detained in Iran," Obama said.

He cited Washington Post journalist Jason Rezaian, Pastor Saeed Abedini, and former US Marine Amir Hekmati, maintaining that all of them "should be released."

Obama also said Tehran should aid the US in finding retired FBI agent Robert Levinson, who has gone missing since 2007.

The President also used the occasion to hit back at critics of the nuclear agreement with Iran, saying the negative remarks come from "the same people who rushed into war with Iraq."

He accused critics of "chest beating," dismissing them as those who just give off sound bites in their effort to obstruct the fragile accord, which has already been unanimously endorsed by the UN Security Council.

In a related development, the Washington Post has petitioned the UN's Working Group on Arbitrary Detention to help in securing the freedom of its Tehran correspondent, Rezaian, The Guardian wrote.

Rezaian has been detained in Iran for 365 days even as the US worked with other countries to reach the landmark nuclear deal.

The petition accused the Iran government of "numerous violations of international laws" for Rezaian's lengthy detention and poor treatment.

"Every aspect of this case – his incarceration, his trial, his unjust imprisonment – has been a disgraceful violation of human rights and it violates common decency," said Washington Post executive editor Martin Baron before reporters.