A notorious arms dealer who has been the subject of an extended diplomatic tug of war between the United States and Russia has been extradited from Thailand aboard a US government jet.

Viktor Bout is a former Soviet air force pilot and alleged KGB agent, who is accused of running arms into just about every major armed conflict and insurrection - from Sierra Leone to Afghanistan - for the past 20 years.

The burly Russian's luck ran out when he was caught in a sting operation by US agents posing as guerillas from the Revolutionary Armed Forces of Columbia (FARC).

It is claimed that in a series of covert meetings that also took him to Denmark and Romania, he agreed to supply the agents with surface-to-air missiles.

He was nabbed in a five-star hotel in Bangkok and since then has fought a two-year legal battle to avoid extradition to the US on charges of conspiracy to kill US nationals and providing material support or resources to terrorists.

If convicted by a US court he faces life imprisonment.

His detention brought repeated protests from Russia which called the extradition proceeding politically motivated, sparking speculation he may be party to sensitive information that could embarrass Russia.

His appearances in court, wearing a bulletproof vest and shackles while flanked by armed police commandos and tearful performances by his wife Alla, added to the drama of the case.

Indeed, his exploits were the inspiration of the Hollywood film Lord of War, starring Nicolas Cage.

Bout has maintained his innocence.

He speaks six languages and used multiple false identities and disguises as he allegedly bought everything from warplanes and helicopters to missiles and small arms at bargain rates after the fall of the Soviet Union and sold them in Afghanistan, Angola, the Democratic Republic of Congo, Liberia, Rwanda, Sierra Leone and Sudan.

Former British foreign minister Peter Hain dubbed him "the Merchant of Death".

Amnesty International has alleged he operated a fleet of more than 50 planes to spread death and destruction across the globe.

He thwarted extradition in August, leaving a US plane sent to collect him sitting on the tarmac when his lawyers insisted that extra charges of money laundering, filed by the US to speed up his extradition, be heard.

Today there were no last-minute hitches and Bout was whisked from his prison in a heavily guarded motorcade and onto a waiting plane, leaving his wife at the prison waiting and unable to say goodbye.

Russia's foreign ministry released a statement saying Bout's extradition was unjustified and unlawful.

But the US government denied it had broken international law in the extradition, with a State Department spokesman calling it "fully consistent with both our bilateral treaty obligations with Thailand and fully consistent with international law."