Former Soviet military officer and international arms dealer Viktor Bout, nicknamed the 'Merchant of Death' and whose colourful life partly inspired a Hollywood movie, has been found guilty of trying to sell heavy weapons to Colombian rebels.

The verdict brings a dramatic end to one of New York's most high-profile trials in recent years. It also put a stop to the career of the world's most notorious arms dealer who prosecutors argued has provided weapons that have fuelled bloody conflicts around the world.

Bout, 44, had denied any wrongdoing in the case, which alleged he had been willing to sell a vast amount of lethal weapons and ammunitions to the Colombian rebel group the Farc, which he knew could be used to "kill Americans" who were helping the Colombian government. The shipment was to have included surface-to-air missiles, 20,000 machines guns, grenades, mortars, high explosives and 10m rounds of ammunition. Bout had argued that he was merely a businessman who happened to run an air freight operation in conflict zones.

Bout was caught in an elaborate sting operation by the US Drug Enforcement Agency, whose informants posed as weapons buyers for the Farc. He was arrested in Thailand where he had believed he was to be meeting the buyers, and was then extradited to the United States.

Anti arms-trade campaigners enthusiastically welcomed the news of the guilty verdict.

"The verdict in the Viktor Bout trial closes the book on one of the most prolific enablers of war, mass atrocities and terrorism in the post-Cold War era. We should all be grateful that the world is safer now that the man who armed the hotspots of the globe is behind bars," said Kathi Lynn Austin, executive director of the Conflict Awareness Project and former United Nations investigator, who had followed the trial.

Some experts used the verdict to call for a tightening of international controls on the arms trade, saying Bout's career had long flouted huge loopholes which allowed the easy spread of weaponry into the world's conflicts.

"It is tragic that because we have no global treaty regulating the activities of arms dealers, many other unscrupulous dealers and brokers will continue to operate … we can't rely on well-paid informants to catch all rogue traders. The answer is better global regulations," said Oistein Thorsen, an arms trade
campaigner at Oxfam International.

Lawyers for Bout had offered what prosecutors called the "planes defence" where they claimed that their client had no intention of selling any weapons but acted like he had so he could sell two old cargo aircraft for $5m. But prosecutors had poked holes in the defence with the use of secretly recorded conversations in Bangkok between Bout and the informants he believed were acting for the Farc.

On one tape an informant said that he wanted to kill Americans in Colombia.

"Kill them, and kick them out of my country," the informant said on the tape. "They don't care where they go any more.

"They go here, they go there. They go wherever they want. Why?"

Bout was quoted as replying: "Yes, yes, yes. They act as if … as if it was their home."

The informant then testified that during the same conversation, Bout wrote down a list of weapons he could provide on a sheet of paper and told him: "And we have the same enemy."

Asked what that meant, the informant responded: "He was referring to the Americans."

Bout's case was also hit by the testimony of his business associate, South African Andrew Smulian, who took the stand against him as part of a plea deal.

Smullian, 70, was accused of the same crimes as Bout. He pleaded guilty to all counts and agreed to testify against his former associate, hoping to reduce his own prison sentence, a minimum of 25 years.

Smulian said that Bout had said that for a downpayment of $20m he could air-drop 100 tonnes of weapons into Colombia. It was Smulian who had initially approached Bout in Moscow about setting up the deal with the Farc.

Bout now faces the possibility of life in prison at a sentencing hearing in February. He hugged one of his legal team as he left the court room. Defence lawyer Kenneth Kaplan expressed disappointment at the verdict.

"It was a tough case," he said afterwards.

But Manhattan attorney general Preet Bharara welcomed the court decision. "Viktor Bout was ready to sell a weapons arsenal that would be the envy of some small countries. He aimed to sell those weapons to terrorists for the purpose of killing Americans. With today's swift verdict, justice has been done and a very dangerous man is behind bars," Bharara said in a statement.

Bout's personal history is shrouded in mystery, as is much of the detail of his career, as he spent several decades criss-crossing the world and doing business in some of the globe's deadliest war zones. He is believed to have sold arms to a dizzying array of countries and rebel movements often playing both sides of the same war.

Bout's dealings have included the US, the Taliban, the Northern Alliance and various groupings in Africa from Congo to Sierra Leone. His career became so notorious that the Yuri Orlov character played by Nicholas Cage in the 2005 film Lord of War is believed to have been partly based on Bout.