“I plead not guilty to all the counts,” Abdullah said during his arraignment.

At the direction of al-Shabaab, the Somalia-based affiliate of al-Qaeda, Kenyan national Cholo Abdi Abdullah conspired to hijack aircraft in order to conduct a 9/11-style attack in the United States, in what federal prosecutors called a “chilling callback” to Sept. 11.

Abdullah was arrested in July 2019 in the Philippines on local charges and arrived in the United States Tuesday for prosecution. He appeared briefly via telephone Wednesday from MCC-Manhattan, where he is being held.

“I plead not guilty to all the counts,” Abdullah said during his arraignment. He was ordered held without bail. He will return to court Jan. 6.

In preparation for the attack, the indictment alleges that Abdullah obtained pilot training in the Philippines, researched security on commercial airliners and how to breach a cockpit door, and also researched information about the tallest building in “a major U.S. city,” which the indictment did not identify.

“This chilling callback to the horrific attacks of Sept. 11, 2001, is a stark reminder that terrorist groups like al-Shabaab remain committed to killing U.S. citizens and attacking the United States,” acting U.S. Attorney Audrey Strauss said.

Abdullah allegedly worked at the direction of a senior al-Shabaab commander who planned the 2019 attack on a Nairobi hotel that killed 21 people, including a U.S. citizen who had survived the Sept. 11 attack.

Abdullah obtained a pilot’s license in the Philippines and sought information about how to obtain a U.S. visa, the indictment said.

“Nearly 20 years after the 9/11 terrorist attacks, there are those who remain determined to conduct terror attacks against United States citizens. Abdullah, we allege, is one of them,” the FBI’s Bill Sweeney said.