Moscow: Syria's deputy oil minister has announced his defection, saying he was joining the uprising against President Bashar al-Assad, as reported.

"I, Abdo Hussameldin, deputy oil and mineral wealth minister in Syria, announce my defection from the regime, resignation from my position and withdrawal from the Baath Party. I am joining the revolution of the people who reject injustice and the brutal campaign of the regime," Hussameldin said in a video posted on YouTube.

Hussameldin is the highest ranking civilian official to abandon al-Assad since the unrest began a year ago.

He also accused Russia and China of backing al-Assad, and said they were "partners in the killing of the Syrian people".

The two countries had vetoed a UN Security Council resolution on Syria, saying it was "unbalanced" and did not contain measures against armed opposition groups.

More than 7,500 people have been killed in violence in Syria over the past 12 months, according to the UN.

Hussameldin's announcement came after US Defence Secretary Leon Panetta said Washington was considering an "array of non-lethal assistance" to the Syrian opposition but that unilateral US miltary action would be a "mistake".

Meanwhile, Russia's UN envoy Vitaly Churkin has accused Libya of running a training centre for Syrian rebels who were "sent to Syria to attack the legal government".

"This is completely unacceptable. This activity is undermining stability in the Middle East," Churkin told the UN Security Council.