Advocacy group denounces California shooting while saying it has been a target of anti-Islam hate calls and threats.

The largest Muslim advocacy group in the United States has raised concerns of a backlash following the deadly California shooting with reports of a threat of violence received at one mosque and many hate calls.

Ibrahim Hooper, spokesman for the Council on American-Islamic Relations (CAIR) in Washington DC, on Thursday condemned the killing of at least 14 people in San Bernardino, while pleading “to not generalise from the acts of individuals to an entire faith community”.

US authorities said they were still investigating the motive behind the shooting spree, allegedly carried out by the suspects Syed Farook, 28, and his wife Tashfeen Malik, 27. Reports said they were heavily armed with guns, bombs and ammunition.

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Following the shooting, the New York Post – the Rupert Murdoch-owned tabloid newspaper – ran a banner headline calling the two dead suspects “MUSLIM KILLERS”. The paper later changed the headline.

“It’s completely outrageous that the New York Post would use that front-page headline,” Hooper told Al Jazeera.

He called the newspaper “irresponsible”, but added he was not surprised because “it is known for its anti-Muslim bigotry”.

“It’s inflammatory and we believe it incites hatred against all Muslims, not just against the people who allegedly carried out the San Bernardino attacks.”

Phone threats

As the names of the suspects were reported on Wednesday, the Manassas Mosque in Virginia received a voice message from an anonymous male caller threatening he would do to worshippers at the mosque what had been done to the victims in San Bernardino.

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The mosque’s imam, Abu Nahedian, told Al Jazeera he received the half-minute profanity-laced message, forwarded to his personal phone, shortly before 11pm on Wednesday (0400 GMT Thursday).

Nahedian said he reported the incident to police, who were investigating the call along with the Federal Bureau of Investigation (FBI).

Sgt. Jonathan Perok, Prince William County Police spokesman, confirmed to Al Jazeera that his office received a report of a threat against the Manassas Mosque.

Perok said that to his knowledge it is the first time the mosque reported receiving such a type of threat.

“This is under investigation and we are reviewing the information provided,” he said.

Nahedian has been preaching at the mosque for more than 20 years, he said. In 2014, the Manassas Mosque was also vandalised.

He blamed a lack of education and awareness about Islam on the threats, saying educated people “know that we [Muslims] are the also victims” of violence.

Nahedian said worshippers at the mosque had been subjected to verbal abuse and other threats even before the San Bernardino attack had happened.

“This is part of our life anyway,” he said. “But we always teach the congregation to be kind to people, and to let your action be the defender of your faith.”

Spewing hatred

At CAIR’s heaquarters in the US capital, Hooper reported that he and his staff had received “lots and lots of hate messages” on Thursday.

“Most of them are just spewing hatred against Islam and Muslims, which is not illegal,” Hooper said.

In California, where the shooting happened, Ojaala Ahmad, spokesman of the state’s CAIR office, said Muslim Americans were as “heartbroken” about what happened as the rest of the country.

She admitted that she also became worried after hearing the identities of the attackers.

“I think it has become very common now that every time a Muslim person might be the perpetrator, the public and the media are quick to say that this was an act of terror without investigating what the actual motives were,” Ahmad said.

But in California anti-Islam sentiment “is not that blatant” as in other states, said Ahmad, and the Muslim community received “overwhelming support” from inter-faith advocates.

“They are saying that they support us and that they know that Islam is not a bad religion, and for us to stay strong in times of what we might be facing in the coming days with the anti-Muslim climate,” Ahmad said.