A California man who threatened to kill all the members of a Los Angeles area mosque and had amassed rifles, shotguns, handguns, high-velocity magazines and "thousands of rounds of ammunition" has been charged with making terrorist threats.

Mark Feigin, 40, called the Islamic Center of Southern California twice and "threatened to kill the person who answered the phone along with other members of the center because of [his] hatred for Muslims and his belief that Muslims will destroy the United States," L.A. police commander Horace Frank told reporters on Tuesday.

A police search of Feigin's home uncovered numerous rifles, shotguns, handguns, high-capacity magazines and "thousands of rounds of ammunition," Frank said. "We believe he certainly had the means to carry out these threats, and that's why we took action."

Omar Ricci, a spokesman for the Islamic Center of Southern California, said that the threats and Feigin's arrest had left the mosque's members "a bit shaken" and that news of the weapons found in Feigin's home had initially conjured images of "a Columbine-type event" in his mind.

Ricci, who spoke alongside Los Angeles police and community leaders during the Tuesday news conference, said the mosque had experienced harassment before. "Unfortunately, in today's political climate, such hate is not uncommon." But he said Feigin's threats rose to a new level of concern. Ricci praised the police force for its response.

It's unclear whether Feigin, who police said was out on a $75,000 bail, had any previous connection to anti-Muslim groups.

However, a person who knows Feigin said the charge against him was not surprising. "He's not of stable mind," said the person, who spoke on the condition of anonymity out of fear. The person said Feigin had made threats against others in the past, "but I don't know if it was in a religious capacity."

The person said Feigin had previously made disparaging comments about Muslims and had shown an interest in weapons. He is "smart," a college graduate, is not married and has no children, the person added.

Frank said police had found no evidence that Feigin was part of an organized group but cautioned that his case is still under investigation.

Police also said they were investigating anti-Muslim Twitter messages in connection with the case but declined to say whether Feigin posted the tweets, citing the ongoing investigation.

Feigin's alleged threats against the Islamic Center, a felony charge, carry a hate crime enhancement. Police are investigating the legality of the weapons found in his home, Frank said. He said it is possible that Feigin may face further charges.

Asked whether Feigin might be able to acquire more weapons, Frank said that it was "certainly a possibility" but that police would "keep an eye on that."

Frank encouraged other victims of hate crimes to come forward. "If you are the victims of crimes such as these, we encourage members of the Muslim community to bring them to our attention because we take them very, very seriously," he said.

Law enforcement officials in several cities say there has been a spike in threats and crimes against Muslims over the past year. Muslim community leaders have frequently cast the blame for such actions at anti-Muslim political rhetoric in the 2016 presidential campaign, and particularly from Republican candidate Donald Trump.