Beirut: Qatar is working to help free four Americans held hostage in Syria by various armed groups, a Gulf source familiar with the matter said on Monday, a day after the Gulf Arab country’s diplomacy helped free a journalist held since 2012.

The source declined to name the four or provide details, and Reuters could not independently verify the assertion, but his account was broadly supported by other sources.

The reported initiative by Qatar coincides with an effort by Doha to rebut accusations by some of its Arab neighbours and Western politicians that it supports the most anti-Western militant armed groups in Iraq and Syria. Qatar does back some rebel factions fighting to oust Syrian President Bashar Al Assad, has mediated the release of foreign and Syrian captives on several occasions in the course of Syria’s three-year-old civil war.

Its latest foray into hostage diplomacy brought Sunday’s release of Peter Theo Curtis, an American held for nearly two years by Al Nusra Front, an affiliate of Al Qaida.

“Four other Americans who have gone missing in Syria have now been located, and Qatar is working to free them,” the Gulf source told Reuters on condition of anonymity. He said the hostages were being held by “various groups” but declined to give details.

Qatar this week argued its aims in the region were peaceful and humanitarian, issuing a statement condemning what it called Foley’s “barbaric” murder.

Qatari Foreign Minister Khalid Al Attiyah said earlier this year his country’s mediation had secured the release in March of 13 Greek Orthodox nuns after more than three months of being held by Islamist fighters. The British-based Syrian Observatory for Human Rights identified the rebels who took the nuns as the Al Nusra Front.

Before that, Qatar helped win the release of 11 Lebanese Shiites in October 2013 after 17 months in captivity in Syria.

While the details of how Qatar managed to get Curtis free are yet to become clear, the Gulf source said Qatari intelligence acting at the request of the United States had obtained video proof that Curtis was alive, something that had allowed negotiations for his release to begin.

“The kidnappers had asked for ransom, but that’s not something Qatar gets involved in,” the source said without elaborating.

The source said Qatar had been willing to try to help free hostages held by various Islamist groups, but found it hard to work with Islamic State of Iraq and the Levant (Isil), whose militants have taken responsibility for killing Foley.