White nationalist James Reardon. Photo: Handout via Reuters.

An Ohio man whom authorities said is a self-described white nationalist is in custody on charges that he threatened to attack a local Jewish community center.

James Reardon, 20, was being held on $250,000 bond on Sunday on charges of aggravated menacing and online harassment, according to records from the Mahoning County Sheriff’s Office.

Authorities found weapons, ammunition, body armor and a gas mask at his house, local media reported.

Reardon was arrested in his hometown of New Middletown late on Friday after investigators became aware of a post on Instagram that appeared to threaten the Jewish Community Center of Youngstown, according to a statement from the Youngstown Area Jewish Foundation.

A user named “ira_seamus” uploaded a video in July showing a man shooting what looked like a semi-automatic rifle, with the sound of screaming and sirens audible over the gunfire. The caption read, “Police identified the Youngstown Jewish Family Community shooter as local white nationalist Seamus O’Rearedon.”

“We subsequently learned that ira_seamus was an online pseudonym for James Patrick Reardon,” Andy Lipkin, the Jewish federation executive vice president, said in a statement. Lipkin said he and other federation officials stayed in “constant contact” with local authorities and the FBI on Friday evening while arranging for increased security at the JCC and other area facilities.

It was not immediately clear whether Reardon had a defense attorney.

A spokeswoman for the Federal Bureau of Investigation confirmed the agency assisted in the investigation but declined to offer details. Police in New Middletown were not immediately available for comment.

Other posts on the Instagram account included anti-Semitic and racist comments, according to WYTV, a local ABC affiliate in Youngstown.

Reardon participated in the violent white nationalist rally in Charlottesville, Virginia, in 2017, the station reported.

“This is a person that has declared himself as a white nationalist,” the police chief in New Middletown, Vincent D’Egidio, told the station. “With the hate crimes and everything else going on, we want to make sure we do our part to make sure we did our part to make sure this person was taken off the streets very quickly.”