PARIS (AP) — The United States and its international partners called today for global sanctions against Bashar Assad’s regime, seeking to step up the pressure after the defection of a top general dealt a blow to the Syrian leader. Washington urged countries around the world to pressure Russia and China into forcing Assad to leave power.

A Western official told The Associated Press that Syrian Brig. Gen. Manaf Tlass had abandoned Assad’s regime. Tlass was a member of the elite Republican Guards and a son of a former defense minister. The official wasn’t authorized to divulge the information and spoke on condition of anonymity.

Tlass’ whereabouts are unclear. The Britain-based Syrian Observatory for Human Rights and other opposition websites claimed he had fled to Turkey. It is arguably the highest profile departure from the Assad regime in 16 months of brutal government crackdowns and civil war.

In Paris, Secretary of State Hillary Rodham Clinton joined senior officials from about 100 other countries to win wider support for a Syrian transition plan unveiled last week by U.N. mediator Kofi Annan. Joined by America’s allies, she called for “real and immediate consequences for non-compliance, including sanctions,” against the Assad regime.

But with neither Moscow nor Beijing in attendance, much remained dependent on persuading the two reluctant U.N. veto-wielding powers to force Assad into abiding by a cease-fire and the transition strategy.