Viktor Bout, 41, was arrested in March in Bangkok during a joint police operation led by agents from the U.S. Drug Enforcement Administration (DEA).
"We have official confirmation that Thailand has received the [Bout's] extradition request," the embassy's press secretary, Alexei Bulkin, said.
U.S. authorities officially brought charges against Bout earlier this week. DEA prosecutors claim that Bout conspired with others to sell millions of dollars worth of weapons to the Revolutionary Armed Forces of Colombia, a leftist group listed by the U.S. as a terrorist organization.
If convicted, he could face life imprisonment or, at the very least, a long prison term.
Thai authorities said in April that they would not bring charges against Bout, but would keep him in custody pending a decision on a U.S. extradition request.
Bulkin reiterated that Russian diplomats would continue protecting Bout's rights and would closely monitor the developments in his case staying in contact with Thai authorities.
Bout is a former lieutenant in the Russian military who quit the armed forces in 1991. He then allegedly transformed himself into an international arms dealer, earning the nickname 'the Merchant of Death.' The Western media has consistently referred to him as a "former KGB officer."
Western law enforcement agencies consider him to be "the most prominent foreign businessman" involved in trafficking arms to UN-embargoed destinations.
UN reports say Bout set up a network of more than 50 cargo aircraft around the world to facilitate his arms shipments.
U.S. authorities took measures against Bout in 2005, freezing his bank accounts and submitting a list of 30 companies linked to Bout to the UN Security Council Sanctions Committee.
