A U.S. citizen and former New Yorker accused of becoming a sniper for the Islamic State group stood silent as his lawyer entered a not guilty plea for him on Wednesday, with the lawyer saying afterward that her client had refused to do it himself.

Ruslan Maratovich Asainov “lives by Sharia law,” defense attorney Susan Kellman said following his arraignment on terrorism charges in federal court in Brooklyn. “He doesn’t abide by the American legal system.”

U.S. District Judge Nicholas Garaufis agreed to keep Asainov locked up under tight security after prosecutor Saritha Komatireddy told him that he was a flight risk and danger to the public because he still considers himself a “citizen of the Islamic state.”

Asainov, 43, “subscribes to the violent ideology of ISIS” and if given the chance “would take up arms again” for the terrorist organization, the prosecutor said.

According to court papers, the naturalized U.S. citizen born in Kazakhstan lived in Brooklyn from 1998 to 2013 before using a one-way ticket to fly from Kennedy Airport to Istanbul in December 2013 to make his way into Syria.

Based on information from another person who supported the IS group during the same period, the defendant trained as a sniper and eventually reacheds a high enough rank that other fighters referred to him as a sniper “emir,” or chief, the papers say. He was also tasked with helping establish training camps where he was a weapons instructor, they add.

While in Syria, Asainov sometimes sent messages with photographs from the battlefield showing he and other IS fighters in combat gear, the papers say. In one from 2014, he described the group as the “real deal” and said that his “faith in Islam had been renewed” since arriving there, they say.

The defendant once tried to recruit a confidential informant to travel to Syria to fight for the group, the papers say. He “claimed that because the CI was fluent in English, he would be particularly suited to support ISIS’s media operations,” they add.

Authorities announced in July that U.S.-backed forces in Syria had captured Asainov and turned him over to the FBI.

(AP)