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.
In pictures: Anti-Isis protests in Jordan
In pictures: Anti-Isis protests in Jordan
1/15 Amman, Jordan
Members of Jordan's Al Assaf tribe burn a ''Wanted Dead'' poster of Islamic State leader Abu Bakr al Baghdadi at a rally
2/15 Amman, Jordan
Jordanian protesters carry an effigy of leader of the militant Islamic State Abu Bakr al-Baghdadi, during a march after Friday prayers in downtown Amman
3/15 Amman, Jordan
Jordanian Queen Rania (C) holds a placard during a demonstration to express solidarity with the pilot murdered by the Islamic State
4/15 Amman, Jordan
A protester dressed in a Jordanian flag joins others as they hold up pictures of Jordanian King Abdullah and Jordanian pilot Muath al-Kasaesbeh, while chanting slogans during a march against Islamic State
5/15 Amman, Jordan
Jordanians hold banners shouting slogans during a demonstration to express their solidarity with the pilot murdered by the Islamic State
6/15 Amman, Jordan
Jordanians carry banners and pictures of executed Jordanian pilot Muath al-Kassasbeh while shouting slogans against the group calling themselves the Islamic State, during a march after noon pray in downtown Amman
7/15 Amman, Jordan
Protesters hold up pictures of Jordan's King Abdullah and pilot Muath al-Kasaesbeh as they chant slogans during a rally in Amman to show their loyalty to the King and against the Islamic State
8/15 Amman, Jordan
Jordanians chant slogans to show their support for the government against terror during a rally
9/15 Amman, Jordan
Jawdat al-Kaseasbeh, a brother of slain Jordanians pilot Muath al-Kaseasbeh, reacts to people gathering to show their support for the government against terror during a rally
10/15 Amman, Jordan
A Jordanian protester kisses a poster bearing the image of Jordanian pilot Muath al-Kasaesbeh during a rally to show their loyalty to King Abdullah and against the Islamic State
11/15 Amman, Jordan
A Jordanian shouts slogans during a rally against the Islamic state group and in reaction to the burning alive of Jordanian pilot Maaz al-Kassasbeh by the group's militants
12/15 Amman, Jordan
Jordanians carry pictures of pilot Maaz al-Kassasbeh at a protest against Islamic State
13/15 Amman, Jordan
Supporters and family members of Jordanian pilot Lt. Muath al-Kaseasbeh express their anger at his murder at the tribal gathering chamber in Amman, Jordan
14/15 Aye Village, Karak, Jordan
The King of Jordan, Abdullah II (L), embracing Safi al-Kassasbeh (R), the father of the recently executed Jordanian pilot
15/15 Aye Village, Karak, Jordan
Jordan's Queen Rania offers her condolences to the family of Jordanian pilot Muath al-Kasaesbeh, at their family home of Muath
REUTERS/Petra News Agency
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.
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."
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