A US prosecutor outlined Wednesday how Viktor Bout, the so-called "merchant of death," was trapped by greed into trying to sell undercover agents an arsenal of weapons he expected to be used against US pilots in Colombia.

But in his own opening statement at the start of a closely watched trial in New York, a lawyer for Bout said the Russian had been framed for crimes he never committed.

The lawyers clashed on the first day of testimony in a Manhattan federal court trying Bout on charges that he conspired to sell anti-aircraft missiles and other powerful weapons with the aim of helping Colombia's FARC guerrillas -- designated by Washington as a terrorist group -- to down US helicopters.

Assistant US Attorney Brendan McGuire began by recounting to a courtroom packed with journalists, law enforcement agents and fellow prosecutors a long shopping list of lethal weaponry.

Dramatically, McGuire then paced away from the jury to Bout, jabbed his finger at the ex-Soviet military man, who sat in a neat gray suit, and said: "This man agreed to provide all of it to a foreign terrorist organization."

He put it "into the hands of men that told him they needed to kill American pilots."

According to McGuire, Bout truly believed at a meeting in Thailand in 2008 that he was attempting to sell FARC representatives the arsenal and that the intention was to bring down US choppers.

In fact, the men he met were not Colombian guerrillas but paid agents of the US Drug Enforcement Agency and the meeting was the culmination of an elaborate sting operation to trap Bout, long accused of being the world's biggest black market arms dealer. He was arrested at that meeting and in 2010 he was extradited to New York.

"He jumped at the opportunity," McGuire said. "Why? For the money."

Bout has pleaded not guilty and says that for years he ran an air transportation business with old Soviet cargo planes, but that he never once did an arms deal.

Presenting his case, defense lawyer Albert Dayan told jurors a more complex version of the events leading up to Bout's arrest.

According to Dayan, Bout had already given up his air business and had turned to real estate dealing in his native Moscow. However when the DEA agents approached him, through a former intermediary, he believed he had an opportunity to sell off his last two airplanes -- but he had no intention or interest in dealing with weapons.

Dayan said Bout was "a man who is wrongfully accused in our country, thousands of miles away from his home."

"The simple very profound truth is that Viktor Bout never wanted, never intended to sell arms," he said.

Sitting in court were Bout's wife and teenage daughter, who sat mostly silently and without expression as they listened to a translation of proceedings on headphones.