Jordan vows to 'wipe Isis out completely' as it investigates claim US hostage killed in air strike

The reported death of Kayla Jean Mueller has not been confirmed

Jordan has vowed to hunt down Isis and “wipe them out completely” as it investigated claims an American hostage was killed in one of its air strikes.

Kayla Jean Mueller, an aid worker, was the last known US hostage being held by the militants following a series of beheadings that started in August last year.

Jordan is seeking to avenge the death of air force Lieutenant Muath al-Kasaesbeh, 26, who was burned alive in a cage after being captured by Isis when his plane went down.

Jordanian fighter jets targeted Isis weapons depots and training sites on Thursday and Friday.

The Interior Minister, Hussein al-Majali, told the state-run al-Rai newspaper that Jordan will track down the militants “wherever they are”, and that this week's strikes were “the beginning of an ongoing process to eliminate them and wipe them out completely”.

His vow came the day after Isis claimed Ms Mueller had been killed in a Jordanian air strike in its Syrian stronghold of Raqqa.

The government dismissed the statement as “criminal propaganda” and the US said it had not seen any evidence to corroborate the report.

If Ms Mueller’s death is confirmed, she would be the fourth American to die while being held by Isis.

Yesterday's statement said she was killed with air strikes that hit “the same location for more than an hour”.

Isis published photos claiming to show the bombed site, with a severely damaged three-storey building, but offered no images of Ms Mueller.

There has been no proof of Ms Mueller's death

The statement claimed no Isis militants were killed, raising further questions about its plausibility.

Mohammed al-Momani, a spokesperson for the Jordanian government, said the report would be properly investigated.

“As a first reaction, we think it's illogical and we are highly sceptical about it,” he added.

“How could they identify a Jordanian warplane ... in the sky? What was the American lady doing in a weapons warehouse?

"It's part of their criminal propaganda. They have lied that our pilot is alive and tried to negotiate, claiming he is alive while they had killed him weeks before."

Jordanians hold up a poster of pilot Muath al-Kasaesbeh during a candlelit vigil

Mr al-Kasaesbeh’s death was announced with the distribution of a gory propaganda video last week but intelligence agencies believe he was killed early in January.

American officials said they also were looking Isis’ claims.

Bernadette Meehan, the spokesperson for Barack Obama's National Security Council, said the White House has ”not at this time seen any evidence that corroborates“ it.

"We are obviously deeply concerned by these reports," she added.

A US official said coalition aircraft did conduct bombing near Raqqa yesterday but had had no intelligence to confirm the claim that Ms Muller was dead.

Additional reporting by AP