Russia said Thursday it had grave doubts about the guilty verdict handed down by a US jury to a Moscow businessman dubbed "the merchant of death" for his global arms trafficking.

The larger-than-life tale of Viktor Bout -- a 44-year-old who spoke multiple languages as he criss-crossed Africa and some of the world's most remote hot spots -- inspired the 2005 Nicolas Cage film "Lord of War".

But Bout was on Wednesday ultimately found guilty by a New York jury of conspiring to sell a huge arsenal to individuals designated as terrorists by Washington and to kill US service personnel.

"Today, one of the world's most prolific arms dealers is being held accountable for his sordid past," US Attorney General Eric Holder said in a statement.

The Russian foreign ministry saw the case very differently and angrily accused US authorities of breaking international standards during both Bout's arrest and interrogation.

It said pressure from the White House and poor prison conditions in Manhattan "put in doubt the very basis on which the charge was made and, accordingly, the fairness of the verdict itself."

"Our goal is to ensure his return home," it said in a statement.

Deputy Foreign Minister Sergei Ryabkov said he expected Bout's case to be discussed when President Dmitry Medvedev meets US counterpart Barack Obama for talks at a summit of Asian states in Hawaii this month.

"We have a number of questions and serious questions at that," said Ryabkov, quoted by the ITAR-TASS news agency.

Bout, a former military translator looked despondent in a grey suit with a white shirt as he listened to the jury forewoman read out the verdict reached after fewer than eight hours of deliberations over two days.

Bout could spend between 25 years and life in prison after his February 8 sentencing. His lawyers immediately promised to appeal and the Russian consulate offered continued legal assistance.

Analysts said Russia is particularly nervous about Bout's jailing because of his suspected links with the country's military intelligence service and possible ties to arms trade officials who remain at their posts to this day.

"Although Bout was a lone wolf, you cannot sell weapons on the black market without certain countries' official support," said military affairs commentator Pavel Felgenhauer.

Bout was arrested in Thailand after being caught in a tape-recorded US sting operation and extradited for trial in 2010. He is not targeted by any legal proceedings at home and lived in the open in Moscow.

The Bout case has been one of several irritants in the Moscow-Washington relationship that had begun to improve in 2009 with US President Barack Obama's "reset" of relations with its Cold War era foe.

Moscow is also upset with Washington for blacklisting Russian officials with ties to the controversial conviction and subsequent death in jail of lawyer Sergei Magnitsky, which ignited world concern.

Russia has responded to the travel ban by announcing its own secret list of US officials who cannot enter the country because of alleged rights abuses on their part.

Ryabkov revealed that 11 officials are on the list, including figures linked to the Guantanamo Bay detention centre but did not give any details on their identity.

Several members of the lower house of parliament's ruling party said Bout's conviction proved that more US officials should be kept out of Russia in the future.

"This is exactly why the State Duma submitted a draft (allowing lawmakers) to ask the Russian government to introduce sanctions against foreign citizens who infringe on Russians' rights," said pro-Kremlin Duma deputy Andrei Klimov.

Bout is alleged to have been the biggest private black market arms dealer in the post-Cold War period.

He always denied this and claimed to have worked only as a private air transporter who sometimes carried legal shipments of arms.

Arms expert and longtime Bout critic Kathi Lynn Austin said the verdict "closes the book on one of the most prolific enablers of war, mass atrocities and terrorism in the post-Cold War era."