NEW YORK - A fire at a mosque in Southern California on Friday appears to have been intentionally set, authorities say, and has prompted condemnations and alarm among Muslims  across the United States.

The fire at the Islamic Society of the Coachella Valley mosque is one of several incidents over the past week that officials are investigating as possible backlashes to the San Bernardino mass shooting that killed 14 people and injured 21 others.

Late Friday, authorities said they had detained someone but released no additional details. “A person of interest” was identified, located and detained, pending further investigation, the sheriff’s department said in a statement. Supervisor said he was alarmed that the mosque may have been targeted.

for religious reasons. “It’s horribly lamentable that we would paint any group as undesirables based on the actions of an extremely small number of radical folks that don’t represent the religion in any way,” he said. “If in fact it was done with the mosque as a target. It’s reprehensible, and the people who perpetrated that act should be treated the way we would any other terrorist.”Last year, a shot was fired into the same mosque; no one was hurt. That incident was investigated as a possible hate crime.

The Sheriff’s Department “believes this is an intentional act and we are using all available resources to follow up on any leads that are brought to our attention,” Deputy Armando Munoz, a department spokesman, said in a statement Friday evening. “California Fire and the Bureau of Alcohol, Tobacco, Firearms and Explosives are assisting us with this investigation.” People at the mosque described hearing a “loud boom” and seeing flames, said Reymundo Nour, the mosque’s acting imam, who was not on the site at the time. He said the mosque had been “firebombed.” But Worshipers remained undaunted, and held prayers outside of the mosque anyway.

The mosque is about 75 miles from San Bernardino, where last week a couple who federal officials say were inspired by Islamist extremists. Some Muslims in Southern California and beyond have worried about the potential for reprisals, while leaders of various faiths have called for tolerance. In a statement released Friday evening, U.S. Congressman Raul Ruiz, whose district includes the area in which the mosque is located, called on authorities to investigate the blaze as a possible hate crime.

“Our faith in humanity will not be intimidated,” he said. “And we stand together against any form violence towards the innocent.”County and city officials also condemned the attack. “We see this as a cowardly act of vandalism that we not tolerate in our community,” Coachella Mayor Steven Hernandez said. The mosque was hit by gunfire in November 2014 in what authorities investigated as a possible hate crime. No one was injured in the early morning incident. The case remains under investigation, and no arrests have been made.

Meanwhile, former Maryland Governor Martin O’Malley became the first 2016 presidential candidate to visit a mosque while on the campaign trail. O’Malley, who is seeking the Democratic nomination, addressed Muslim-Americans at the All Dulles Area Muslim Society (ADAMS) Center Mosque in Sterling, Virginia. on Friday.    During his speech, O’Malley expressed a message of solidarity, saying that the recent terror attacks carried out by Muslims don’t reflect on the community as a whole. “In these times, I suppose — where fear and division is in the air, it is easy for unscrupulous politicians or hate preachers — no nation is immune from the scourge of hate preachers — to turn us upon ourselves.  But that sort of language that you hear from Donald Trump is not the language of America’s future,” O’Malley said.

“I know the language of America’s future.  I speak to our young people under 30 every day, and I rarely find among them any who feel like Donald Trump.”   O’Malley said he knows that the nation’s young people understand that the tragic murders that took place in San Bernardino, California,  don’t define Islam “any more than that horrible murder that took place in Charleston defines Christianity.”    “The world has never needed America to act like America more than right now,” O’Malley said. “To appreciate that we’re all in this together — that each of us a dignity and a freedom and a calling.  

And that each person is needed.” Republican presidential candidate Donald Trump has come under fire for suggesting that all Muslims who are not U.S. citizens should be temporarily banned from entering the country.    Though some of his rival Republicans have criticized Trump’s position, none have discounted him as a potential nominee in their party. And while the leading Democratic candidates, former secretary of State Hillary Clinton and senator Bernie Sanders, condemned his proposal, neither has held an event with the Muslim community since violence in San Bernadino.