Russia's envoy to the UN has accused Libya of running a training center for Syrian rebels combating the "legal government" of President Bashar al-Assad.
"We are concerned by reports that in Libya, with the support of the authorities, there is a special training centre for the so-called Syrian revolutionaries," Vitaly Churkin told the UN Security Council on Wednesday.
Churkin said the rebels were sent to Syria to "attack the legal government."
"This is unacceptable," he said. "This activity is undermining stability in the Middle East."
More than 7,500 people have been killed since the uprising against President Assad began a year ago. The government blames the violence on "terrorists and armed gangs."
Russia is the biggest supplier of arms to Syria and has use of a naval base there. Russia and China vetoed a UN Security Council resolution on Syria last month, saying it was "unbalanced" and did not contain measures against armed opposition groups.