The Syrian ambassador to Iraq has defected, denouncing President Bashar Assad in a TV statement Wednesday, becoming the most senior diplomat to abandon the regime during a bloody 16-month uprising.

Nawaf Fares, a former provincial governor, is the second prominent Syrian to break with the regime in less than a week. Brig. Gen. Manaf Tlass, an Assad confidant and son of a former defense minister, fled Syria last week, buoying Western powers and anti-regime activists, who expressed hope that other high-ranking defections would follow.

The high-level defections could be a sign that Assad's tightly wrapped regime is unraveling, but it was too early to be certain. There have been thousands of defections in the past, mostly low-level army conscripts, but until now no one as senior as the general and the ambassador had fled.

In a statement broadcast on the Arabic satellite channel Al-Jazeera, Fares said he was resigning and joining the opposition. Wearing a dark suit and reading from a prepared text in what appeared to be a large office, Fares harshly criticized Assad.