(Adds details, quotes)

By Edith Honan and Nopporn Wong-Anan

BANGKOK/NEW YORK, March 6 (Reuters) - Viktor Bout, an international arms dealer dubbed the "Merchant of Death," was arrested in Thailand and charged in New York on Thursday with trying to sell weapons to Colombian rebels, officials said.

Bout, the target of U.S. sanctions, was charged with conspiring to sell millions of dollars worth of weapons to the Revolutionary Armed Forces of Colombia, or FARC, U.S. Attorney Michael Garcia said in New York.

The United States, which has given billions of dollars in military aid to Colombia to fight the Marxist rebels and drug cartels, plans to pursue Bout's extradition from Thailand, officials said.

Bout and an associate, Andrew Smulian, are charged with agreeing to sell to the FARC millions of dollars in weapons, including surface-to-air missile systems and armor-piercing rocket launchers, between November 2007 and last month.

Smulian, 46, was charged on Thursday with conspiring to provide material support to a terrorist organization. Smulian's whereabouts where not immediately clear.

If convicted, both men face a maximum sentence of 15 years' in prison.

The FARC are fighting a four-decade-old insurgency against the Colombian government and are designated as a foreign terrorist organization by the U.S. State Department.

"Viktor Bout and Andrew Smulian agreed to arm terrorists with high-powered weapons that have fueled some of the most violent conflicts in recent memory," Garcia told a news conference.

"They face charges in the United States for agreeing to provide weapons to a terrorist organization that has threatened and continues to threaten American interests."

The group is at the center of a diplomatic dispute that threatened to erupt into military conflict this week, after Colombia crossed into Ecuador to attack FARC rebels and kill one of their commanders on Saturday.

Venezuela, an ally of Ecuador and U.S. antagonist, jumped into the dispute, and the two countries sent extra troops to their borders with Colombia.

FORMER SOVIET OFFICER

Bout -- a former Soviet air force officer born in Tajikistan in 1967, according to Russian media reports -- was picked up at a Bangkok hotel after entering Thailand on Feb. 29. Police were searching for an associate.

He was attempting "to procure weapons for Colombia's FARC rebels," Thai police said in an arrest report.

Bout has run a network of air cargo companies in the Middle East, Africa, Eastern Europe and the United States.

According to the United Nations and the U.S. Treasury Department, Bout has sold or brokered arms that have helped fuel wars in Afghanistan, Angola, the Democratic Republic of Congo, Liberia, Rwanda, Sierra Leone and Sudan.

The U.S. Treasury Department seized his cargo planes and froze other assets in 2006.

Bout has repeatedly denied the allegations.

Stephen Rapp, Chief Prosecutor at Sierra Leone's U.N.-backed war crimes court, welcomed the arrest: "It's very good news for justice and for international law enforcement."

He accused Bout of using his international network to smuggle arms through neighboring Liberia to fuel Sierra Leone's 1991-2002 civil war, which killed more than 50,000 people.

Rapp said Bout could be indicted by Sierra Leone's Special Court, which is currently due to close in 2009, if international donors came forward to provide funding.

"These kinds of cases need to be made against not just the politicians and the fighters, but the people who provide weapons of war," he said. "This is a great opportunity."

Rapp said Bout could also be a witness in the continuing trial of former Liberian president Charles Taylor in The Hague. Taylor is accused of crimes against humanity for his role in Sierra Leone's civil war. (Additional reporting by Katrina Manson in Freetown; editing by Michelle Nichols and Todd Eastham)

AlertNet news is provided by