Mr Bout is alleged to have sold weapons in many countries

Viktor Bout - who has been dubbed the "merchant of death" - was picked up by police at a luxury hotel in Bangkok.

The Thai authorities acted on a warrant issued by the US, which accuses Mr Bout of supplying arms to Colombian rebels.

He has also been accused of breaking UN embargoes on arms sales to many countries from central Asia to Africa, but has never been prosecuted.

When Belgium and Interpol issued an international arrest warrant for him in 2002, Mr Bout returned to Russia, where he was protected from extradition by the country's constitution.

Deportation

Lt Gen Pongpat Chayapan, head of the Thai Crime Suppressino Bureau, said Mr Bout was arrested at a hotel in Bangkok shortly after he arrived in Thailand while attempting to "procure weapons for Colombia's Farc rebels".

We will take legal action against him here, before deporting him to face trial in another country Lt Gen Pongpat Chayapan, Thai Crime Suppressino Bureau Profile: Viktor Bout

The left-wing Revolutionary Armed Forces of Colombia (Farc) have been seeking to overthrow the Colombian government for more than four decades.

"We have followed him for several months. He just came back to Thailand today," Gen Pongpat said.

"We will take legal action against him here, before deporting him to face trial in another country, likely the US."

The US warrant stemmed from an earlier one issued by the US Drug Enforcement Administration (DEA), he said.

Unconfirmed US media reports say Mr Bout was arrested during negotiations to sell weapons in a sting orchestrated by a DEA special operations unit.

A spokesman for the US embassy in Bangkok congratulated Thai police on the arrest, but could not provide any details about the possible role of US officials.

The US treasury department imposed sanctions on Mr Bout's businesses in October 2006, seizing his fleet of cargo planes and freezing many of his assets.

UN embargoes

Mr Bout, 41, is said to have graduated from Moscow's military institute in the early 1990s and was a major in the Soviet KGB.

According to a 2007 book about him - entitled Merchant of Death - Money, Guns, Planes and the Man Who Makes War Possible - he set up a network of companies using redundant Soviet military planes.

A 2005 report by the human rights group, Amnesty International, said Mr Bout was "the most prominent foreign businessman" trafficking arms from countries such as Bulgaria, Slovakia, Ukraine and Kyrgyzstan to destinations under UN embargoes.

He has also been accused of supplying weapons to supporters of former Liberian President Charles Taylor, rebels in the Democratic Republic of Congo, the Taleban in Afghanistan and even al-Qaeda during the 1990s.

Mr Bout's life is believed to have been the inspiration for Nicolas Cage's character in the 2005 film, Lord of War.