Russian suspected arms dealer Viktor Bout has pleaded not guilty to terrorism charges, hours after he was extradited to the US from Thailand.
The former Russian air force officer is accused of trying to sell arms to Colombian rebels and supplying weapons used in Africa and the Middle East.
The case has heightened tensions with Russia, where officials said it could threaten co-operation in Afghanistan.
Mr Bout faces 25 years in prison if convicted.
In astatement, US Attorney General Eric Holder called Mr Bout one of the world's most prolific arms traffickers.
Mr Bout is being held without bail in a high-security prison in New York City pending trial. He is next due in court in January.
According to the indictment, in 2007 and 2008 Mr Bout met informants for the US Drug Enforcement Agency in Thailand whom he believed to be agents of the Farc, a Columbian rebel group the US calls a "narco-terrorist organisation".
Prosecutor say he agreed to sell them millions of dollars worth of heavy weaponry, including surface-to-air missile systems, armour-piercing rocket launchers, assault rifles and ammunition, land mines, explosives, night-vision equipment and aircraft.
Mr Bout was subsequently arrested by Thai police in Bangkok. After two years of diplomatic wrangling with Thailand and Russia, he was flown to the US early on Tuesday.
He is charged with conspiracy to kill US nationals and government officers, conspiracy to use an anti-aircraft missile and conspiracy to provide material support or resources to a designated foreign terrorist organisation.
If convicted Mr Bout faces 25 years in prison.