NEW YORK >> A former U.S. solder nicknamed Rambo pleaded not guilty Saturday to charges he plotted with phony Colombian drug traffickers to kill a federal agent for $800,000.

Joseph Hunter, stocky and wearing a wrinkled gray prison jumpsuit, was held after the brief appearance in federal court in Manhattan. His lawyer declined to comment.

An indictment unsealed Friday described the 48-year-old Hunter as a contract killer and leader of a trio of former soldiers who were trained snipers. Hunter, a resident of Thailand, was flown Friday evening to New York after he was expelled from Thailand, U.S. Attorney Preet Bharara said.

Hunter was charged with conspiracy, attempting to import cocaine and plotting to kill a law enforcement agent. When asked by U.S. Magistrate Judge Frank Haas about his plea, Hunter responded: "Not guilty, sir."

According to the indictment, Hunter served in the U.S. Army from 1983 to 2004 before becoming a contract killer who successfully arranged several slayings outside the United States. Authorities didn’t give details.

An informant within the U.S. Drug Enforcement Agency posed as a drug trafficker and proposed to Hunter and his team that they kill a DEA agent and a boat captain providing information to U.S. law enforcement authorities, claiming it was necessary because there was a leak within the narcotics trafficking organization, according to the indictment.

In an email exchange, according to the indictment, Hunter responded: "My guys will handle it. … Are you talking about both the captain and agent or just the captain?"

Audio and video recordings captured Hunter talking about "bonus jobs" of contract killings, claiming the men he recruited wanted as much work as possible, and when assassinations of a federal agent and an informant were proposed, Hunter "didn’t flinch at the chance," authorities said.

Former U.S. solider Timothy Vamvakias, 42, and Dennis Gogel, 27, a German citizen, were also charged in the assassination plot. Both men pleaded not guilty in Manhattan federal court to charges that carry the potential for life imprisonment and were held without bail.