PARIS  - Muslims in France have reacted with fury to the beheading of a fellow citizen by militants, but many warn they too are being “held hostage” by pressure to denounce such acts.

Muslims nationwide have rallied to condemn the execution of 55-year-old mountaineer Herve Gourdel this week by Algerian militants with ties to the Islamic State militants sowing terror in Iraq and Syria.

“It’s heartbreaking, I couldn’t sleep. Those who did this are wild animals,” said Chagour Khaouther, an Arabic teacher in the Parisian suburbs. “I can’t accept that they claim to do this in the name of Islam.”

Gourdel was kidnapped on Sunday by Algerian group Jund al-Khilifa shortly after a chilling call by IS militants for Muslims to kill citizens from countries involved in a US-led coalition fighting the extremists, “especially the spiteful and filthy French.”

The threat raised national security jitters throughout France, where authorities are already battling to prevent would-be militants from going to fight in Iraq and Syria amid fears they will return to commit attacks on home soil. Gourdel’s execution also ratcheted up the pressure that has been mounting on leaders of Europe’s largest community of Muslims - numbering some five million - to take a public stand against IS militants. In an unusual move, the French Council of the Muslim Faith - an official representative for the country’s Muslims - called for a rally against the “horrific and bloody barbarism of the (IS) terrorists” in Paris on Friday afternoon. And leading Muslim figures signed a message published in French newspapers Friday condemning “atrocities committed in the name of a murderous ideology hiding behind the Islamic religion.”

“We are also the ‘filthy French’,” said the statement.

There were also calls on social media for displays of solidarity in several other French cities, including Nantes in the west and Lyon in the east.

Kamel Kabtane, head of the Lyon mosque, said he plans a large interfaith gathering on October 1 “to oppose violence of any kind”.

An interior ministry source involved in Muslim issues, speaking on condition of anonymity, described these reactions as “spontaneous” and a rare occasion in which all Muslim leaders were speaking with one voice.

He said the momentum was largely due to the massive population of some 1.3 million Algerians in France who were “traumatised” by the execution, which recalled the violence suffered by their own people at the hands of extremists. But the demand for a homogenous Muslim response has not gone down well in all quarters.

On Thursday the conservative Le Figaro newspaper prompted an outcry when it ran an online poll asking readers whether they thought the Muslim community’s reaction to Gourdel’s killing was “sufficient”.

Internet users hit back at the “nauseating” and “illogical” question, prompting Le Figaro to withdraw the poll entirely.

“What madness!” said the Rue89 news website, offering up a satirical list of occasions in which people “should have publically distanced themselves” from an issue. “We did not ask Christians to distance themselves from the Ku Klux Klan. We did not ask pop singers to distance themselves from Miley Cyrus,” read an article on the site.

Fateh Kimouche, founder of popular Muslim website Al Kanz, said it was unacceptable that Muslims be “ordered” to react to terrorist acts.

“These summons disgust me, it implies that we are suspect,” she said. “We are held hostage by terrorists, because Muslims are their first victims, and we are held hostage by an Islamophobic fringe which takes advantage of these crimes to spill its hate.”

French anti-Islamophobia group CCIF urged Muslims not to respond to the calls to protest.

“Muslims must not play the Islamophobia game, which consists of ... incessantly pushing them to justify themselves regarding the acts of third parties.”

Mohamed-Ali Adraoui, an Islam expert at Sciences Po university in Paris, said the debate had pushed Muslims into two corners: the evil militants and the good Muslims who condemn them.

“When it suits us, we want Muslims just to be French, we reject communities. But now, they must go on crusade as a single unit,” he told AFP.