A US freelance journalist who was kidnapped in the Iraqi capital Baghdad a week ago has been released, according to Secretary of State Marco Rubio.

Iran-backed militia group Kataib Hezbollah said earlier on Tuesday that it would release Shelly Kittleson, who was taken on 31 March, on the condition that she leave Iraq immediately.

Rubio said the release "reflects the Trump Administration's steadfast commitment to the safety and security of American citizens, no matter where they are in the world".

He thanked Iraqi officials for help securing her release and said the US is now "working to support her safe departure from Iraq".

At the time of the 49-year-old's abduction, the Iraqi government said security forces had chased the suspects in a pursuit that led to one of the kidnappers' cars overturning and the arrest of one person.

Last week, Iraqi Prime Minister Mohammed Shiaa al-Sudani ordered security forces to pursue those responsible for abducting foreigners.

In a separate post, Assaf said the group would release a recording showing Kittleson's "role and activities in Iraq", without providing further details.

The abduction came amid ongoing attacks by Iran and its allied Iraqi Shia militias on US-associated targets across Iraq and the region since the outbreak of the US-Israeli war on Iran.

Kittleson's friend and emergency contact, CNN national security analyst Alex Plitsas, said he had seen the "alleged statement" about her release, but added "we have no official confirmation from the United States government that this is true".

It is understood that US officials had contacted Kittleson a number of times before she was kidnapped to warn of threats against her.

Plitsas previously told CBS, the BBC's US news partner, that Kittleson had been warned by the US government about a specific threat to her from Iran-backed paramilitaries.

He said Kittleson had been told her name was on a list in the possession of Kataib Hezbollah, which was said to be plotting to kidnap or kill female journalists.

Kittleson, based in Rome, Italy, has covered conflicts in Afghanistan, Iraq and Syria. According to her bio on X, she has worked for numerous publications.

The US state department has warned citizens not to travel to Iraq.