Iran is stepping up its support for Syrian President Bashar al-Assad, while Russia is continuing to send money and arms to the regime, US Secretary of State Hillary Clinton warns.
"The Iranians have made it clear for some time that keeping Assad in power was one of their highest priorities. We believe they have acted on that by sending in more personnel, not only to help Assad, but to support and advise military security forces," Clinton said.
In her last media interview as secretary of state, Clinton said there was "a lot of concern that they are increasing the quality of weapons because Assad is using up the weapons, so it's numbers and it's material".
"The Iranians have been actively involved from the very beginning. It appears that they may be increasing that involvement and that is a matter of concern to us," she said.
But Clinton also noted that despite America's efforts to bring Moscow on board to work for an international solution to the 22-month war in Syria that has claimed some 60,000 lives, Russia was continuing to prop up Assad's regime.
"The Russians are not passive bystanders in their support for Assad. They have been much more active on a number of fronts," she said.
"We have reason to believe that the Russians continue to supply financial and military assistance in the form of equipment to Assad."
Clinton also gave a grim assessment of the war's progression, warning of "the dangers of an increasing civil war and a potential proxy war".
"The worst kind of predictions of what could happen … are certainly within the realm of the possible now," she said.