The Syrian opposition says the ambassador to Iraq has defected.

If confirmed, Nawaf Fares would be the highest-ranking diplomat to flee Bashar al-Assad's government since the deadly rebel uprising began 16 months ago. There has been no confirmation from Damascus or Baghdad.

Several top military officers also have defected, as well as a large number of soldiers.

In Washington, White House spokesman Jay Carney calls this a sign that support for Mr. Assad is crumbling both inside his own government and internationally.

United Nations envoy Kofi Annan says that in his talks this week with President Assad, the Syrian leader proposed a negotiator who would represent him in talks with the opposition. Mr. Annan did not reveal a name.

Mr. Annan also said Iran and Iraq told him they would use their influence to push the Syrian opposition into talks. Carney said the United States is not excluding anyone from participating in talks about Syria's future, but he doubts Iran could play a constructive role.