Russia summoned a US diplomat to protest at a Pentagon claim that Russian soldiers spirited away hundreds of tonnes of explosives from a site in Iraq just before the US invasion, Interfax news agency said on Friday.
The missing cache of explosives has become a political hot potato in the US election race, with Democratic challenger John Kerry accusing the administration of President George W. Bush of failing to secure the site.
In a Washington Times story this week, Pentagon official John Shaw pointed the finger at Russian special forces, saying they had moved many of Iraq's weapons into Syria in the weeks before the March 2003 invasion.
"The Russian Ministry of Defence summoned the US military attache in Moscow to express a resolute protest in connection with the comments by John Shaw," Interfax quoted an anonymous source at a Russian defence agency as saying.
A spokesman at the US embassy in Moscow confirmed that a member of the embassy's defence staff had been "called in", but denied it was the chief military attache and declined to say what had been discussed at the meeting.
Russia's Defence Ministry dismissed the allegation that there had been any Russian involvement in the disappearance of the explosives in Iraq.
"You can't really take statements like this as anything but far-fetched rubbish," said spokesman Vyacheslav Sedov.