MOSCOW, November 19 - RAPSI. The Russian Foreign Ministry will continue to do all it can for Viktor Bout, who was sentenced in the United States to 25 years in prison, Foreign Ministry Special Envoy for Human Rights Konstantin Dolgov said.

"We will not drop the case, we will be do all we can for Bout," Dolgov said at a roundtable of the State Duma Committee for International Affairs. Dolgov also called the United States' refusal to extradite Bout a gross violation of international law.

"It is very important that all parties interested in Bout's return to Russia act together, both in terms of statements issued and practical steps taken," he said. Dolgov added that attempts to influence the U.S. authorities are not often unsuccessful, however, "some signals do reach them."

A former Soviet military officer, Viktor Bout was convicted in November 2011 of conspiracy to kill U.S. nationals, including military officers and employees, conspiring to supply man-portable anti-aircraft missiles, and selling millions of dollars worth of weapons to the Colombian rebel group FARC.

Bout, who has consistently denied the charges against him, was sentenced to 25 years in April 2012. He is serving his prison term in the United States Penitentiary, Marion (USP Marion) in Illinois. Russia attempted to have Bout transferred from the United States in line with the 1983 Convention on the Transfer of Sentenced Persons, but without success.