UK: Top Syrian diplomat in London defects

“Ayoubi has told us that he is no longer willing to represent a regime that has committed such violent and oppressive acts against its own people, and is therefore unable to continue in his position,” the statement said.

While traveling to Tunisia, Defense Secretary Leon Panetta said on Sunday that the attacks by Assad’s forces in Aleppo were “a nail in Assad’s coffin.”

“If they continue this — this kind of tragic attack on their own people in Aleppo — I think that it ultimately will be a nail in Assad's coffin,” Panetta told reporters. “He's just assuring that the Assad regime will come to an end by virtue of the kind of violence that they're permitting against their own people.”

Assad’s government has seen multiple defections as the fighting between Assad’s forces and the opposition has intensified, including an elite Syrian Republican Guard unit general who left earlier this month.