At least two U.S. mosques have faced threats since last week's San Bernardino shooting, which killed 14 people and was called "an act of terrorism, designed to kill innocent people" by President Barack Obama in a speech Sunday night. Many have responded to the tragedy with acts of Islamophobia, and it has innocent Muslims in the country feeling frightened and targeted.

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Imam Abu Nahidian, the religious leader and founder of Manassas Mosque in Northern Virginia, told the Washington Post that his religious facility received a voicemail on Thursday from an anonymous person, who threatened to murder the people of his mosque in response to the Southern California attacks. The caller also claimed to be from a Jewish group and said he/she was looking into whether any Jewish people died in San Bernardino.

Nahidian has reported the message to the Prince William County police and was told that the caller could be charged for making a threat and possibly a hate crime if the call can be traced.

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The Manassas Mosque was vandalized a year and a half ago as well, and Nahidian said at the time that the mosque has seen vandalism during times of high tension between the U.S. and Middle East. Last summer, Nahidian told the Washington Post that someone had written an expletive on the windows of the mosque and that eight windows total were defaced.

“We do not hurt anybody," Nahidian previously told the Washington Post. "If those with our names are doing something, why should I become the victim? You haven’t seen me doing anything. We are a part of the whole earth, and we love the whole earth.”

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Nahidian told the Washington Post that "reasonable" people would ask him questions about his faith rather than attack his mosque.

"Then I would tell them, 'No, our faith would never do something like that,'" he said. "ISIS has no understanding of Islam — not only Islam, but humanity. It is not the Islamic State. It is a terrorist state."

The imam personally addressed his harasser in an interview with FOX5:

The Islamic Center of Greater St. Louis also received threats following the San Bernardino attacks. The mosque reported a threatening voicemail to FBI officials, and at least one of the mosque members has been threatened at home, according to local news station Fox 2 Now St. Louis.

"Many here are frustrated by the fact they even feel a need to call a news conference to address something they have no tie to, 1,800 miles away," Fox 2 Now's George Sells wrote on Sunday.

Asif Umar, the Imam of the mosque, told the news outlet that he was born and raised in the city and that others have expressed fear around him for no reason.

Ibrahim Hooper, spokesman for the Council on American-Islamic Relations (CAIR) in Washington, D.C., told Al Jazeera that the office received "lots and lots of hate messages" on Thursday.

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

Ojaala Ahmad, the spokesman of the state's CAIR office, told Al Jazeera that many are quick to assume Muslim perpetrators are motivated by terrorism and don't look into other potential factors.

"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.

Following the recent series of attacks in Paris, for which the Islamic State (also known as IS, ISIS, Daesh, or ISIL) has taken credit, some have blamed Muslims for the atrocities, even though many who practice Islam have condemned the extremist group. In late November, a mosque in Pflugerville, Texas was vandalized with feces in response to the attacks. Though there was a glimmer of hope when a little boy donated all of his piggy bank money to the damaged mosque, overall Islamophobia remains a major issue.

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Following the rise in Islamophobia last month, many Muslims shared the hashtag #NotInMyName, which the Active Change Foundation first launched last year to enable Muslims to call out and criticize the Islamic State. Over the weekend, #YouAintNoMuslimBruv started trending after a video surfaced on Twitter of someone yelling, "You ain't no Muslim, bruv," (slang for "brother") at a man who was being investigated for stabbing others at a London subway station and saying, "This is for Syria."

The clip, which is embedded in the tweet below, paved the way for the #YouAintNoMuslimBruv hashtag, where others exclaimed that extremists don't represent Muslims at large. Prime Minister David Cameron even said, "You ain't no Muslim, bruv" as well:

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During his address to the nation on Sunday night, President Barack Obama said it's important to remember that the Islamic State does not represent Islam.

"We cannot turn against one another by letting this fight be defined as a war between America and Islam," the president said. "That, too, is what groups like ISIL want. ISIL does not speak for Islam. They are thugs and killers, part of a cult of death, and they account for a tiny fraction of more than a billion Muslims around the world -- including millions of patriotic Muslim Americans who reject their hateful ideology."