An 18-year-old high school student on Long Island is facing charges after allegedly making violent threats toward students and faculty at his school, police said.

According to the Nassau County Police Department, Oketa Orlando Blair Jr. was arrested Tuesday in Old Westbury after expressing "his desire to conduct a violent act towards students and faculty members" at Westbury High School. Four days ago, he replied to Twitter posts by the district, threatening to shoot up the school.

Staff allegedly became aware of the threat and the school administration notified police.

Blair Jr. is charged with making a terroristic threat and aggravated harassment in the second degree. An Extreme Risk Protection Order was granted by a judge preventing Blair Jr. from purchasing any firearms.

"We take these threats seriously — in light of what’s going on in this world, we cannot afford not to," said Nassau County District Attorney Anne Donnelly. "I don’t think we can say you're 18 and we didn’t find any guns, that means you’re never going to get violent. It’s too easy to go out and purchase a weapon."

Blair Jr. was suspended from the school in May after he was involved in a series of fights.

He was arraigned Wednesday in Hempstead, and left without speaking to reporters after being released by the judge. He was ordered to wear an electronic monitoring ankle bracelet, and prosecutors said a search of his home address did not turn up any weapons.