Parents of IS's American hostage hope she is alive

The parents of the female US aid worker kidnapped by the Islamic State (IS) refused to believe that she has been killed in Jordanian airstrikes as claimed by her captors, media reported Saturday.

Kayla Jean Mueller, 26, was believed to have been an aid worker with the Spanish Doctors Without Borders.

She was captured by the IS, along with her Syrian boyfriend, in the Syrian city of Aleppo in August 2013 and taken to the de facto IS capital of Raqqa, also in Syria.

She was believed to have been held alongside other prisoners -- some of whom have been shown in the IS regime's trademark beheading videos.

The reports of her death were met with widespread scepticism which her parents, Carl and Marsha, appeared to share.

In a statement released Saturday, the couple from Prescott city in the US state of Arizona, said they were "hopeful that Kayla is alive", Britain's Daily Mail reported.

They begged her captors to contact them privately, and hinted that they had already been in contact with the IS militants, who typically demand enormous ransoms for the return of prisoners.

In contrast to the harshly-treated male prisoners, the Muellers said the jihadis had called Kayla their "guest". The elderly couple urged the militants to live up to the moniker by keeping Kayla safe.

The IS claimed Friday that Jordan's retaliatory airstrikes, following the execution of Jordanian pilot Moaz al-Kasasbeh by the militant group, have led to the death of a US hostage being held by the militants.

A statement released by IS sources said: "The criminal crusader coalition aircraft bombarded a site outside the city of Raqqa... while the people were performing the Friday prayer."

The IS shared photographs of a bombed out building that it claimed had come under Jordanian attack.

The statement could not be independently verified, but initially appeared on a website commonly used by the IS and was also distributed by IS-affiliated Twitter users.

The militants then claimed that the US hostage was inside the building at the time and had been killed.

Reports emerged Saturday that the date on the photographs of the alleged strikes were one day off and there were no images of the hostage herself.

However, Jordan's Interior Minister Hussein Majali had firmly trashed the IS claim, calling it "another PR stunt by ISIS (the earlier name of IS)".

"They tried to cause problems internally in Jordan and haven't succeeded," Majali said. "They are now trying to drive a wedge between the coalition with this latest low PR stunt."

The IS had demanded more than $6 million for the US aid worker's release and was believed to have sent a video of her wearing a burqa (veil) and pleading for her life last August, according to the report, which cited the New York Times.

In August 2013, US officials and Kayla's family had requested that her name not be published for fear of putting her in further danger.

Bernadette Meehan, the spokesperson for the US National Security Council, said the White House has "not at this time seen any evidence that corroborates the claim".

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

White House spokesman Eric Schultz did not say whether the US was aware of the hostage's location.

If the aid worker's death was confirmed, she would be the fourth American to die while in the captivity of the IS militants.

Three other Americans -- journalists James Foley and Steven Sotloff, and aid worker Peter Kassig -- were beheaded by the group.