An American soldier was arrested yesterday by the FBI and the US Army for allegedly attempting to provide tactical advice to help the Islamic State (IS) conduct attacks on New York City and on US forces in the Middle East.

Prosecutors allege that Pfc. Cole James Bridges of the Army’s 3rd Infantry Division offered tips to an undercover FBI informant on how to kill US troops in the Middle East and said that he would side with the jihadists if they ever attacked his unit while deployed, according to a criminal complaint filed in New York.

Investigators also allege he discussed with the informant potential targets for attack in New York City, including bridges, federal buildings and the Sept. 11 memorial in Manhattan.

The complaint noted that Bridges later appeared to have second thoughts about supporting an attack inside the United States but allegedly continued to provide details of American infantry tactics to help his supposed IS contacts kill his fellow troops abroad. He also sent a video of himself posing with a black flag associated with Sunni jihadism and raising his index finger in a gesture common among IS supporters.