Defense lawyers for jailed Russian arms dealer Viktor Bout claim there is new evidence to support their appeal for the case to be reconsidered.

"We have reliable information that representatives of American state agencies exerted pressure, intimidation, and bribery regarding Thai officials who took the decision to extradite Bout to the United States, and that on the basis of these new facts the case should be returned to Judge Scheindlin and canceled," Bout's attorney Albert Dayan told RIA Novosti.

Bout was arrested in Bangkok in 2008, but only extradited to the US in November 2010 after a protracted legal battle against it finally failed when the Thai cabinet backed the US request to send him to America.

Bout's defense has repeatedly claimed that this extradition was illegal, with Judge Sheindlin taking the position that it was not her job to evaluate other countries' laws. This time Dayan is claiming that American officials broke American law.

Dayan visited Bout in prison this week, and noted that he is no longer able to finance his defense.

A former Soviet military officer, Viktor Bout was convicted in November 2011 of conspiracy to kill US 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.

He has continually denied the charges against him. In April 2012 he was sentenced to 25 years behind bars.

Russia's Foreign Minister Sergei Lavrov has reiterated the view that Bout's prosecution was political in nature, and said Russia will do anything it legally can to get him sent home.