White House blames Annan's failure in Syria on China, Russia

The U.S. ambassador to the U.N., Susan Rice, also pointed the finger at Russia and China.

"His mission could never have succeeded so long as the Assad regime continuously broke its pledges to implement the Six Point Plan and persisted in using horrific violence against its own people," Rice said in a statement. "When the Security Council failed to heed Mr. Annan's repeated calls for collective and significant consequences for non-compliance with its prior resolutions, those members who blocked this action effectively made Mr. Annan's mission impossible."

Carney also pointed out that the administration on Thursday approved an extra $12 million in humanitarian aid for people affected by the violence, bringing the total to $76 million. And he said the United States is still only providing nonlethal assistance to the opposition.

“We don’t believe that adding to the number of weapons in Syria is what’s needed to help bring about a peaceful transition,” he said.

Carney also denounced reports that the opposition is executing pro-Assad prisoners.

“We strongly condemn summary executions by either side in Syria. We condemn actions like that. ... It’s important to note that it is Assad’s regime and Assad’s forces that have perpetrated the overwhelming amount of the violence in Syria and are responsible for the overwhelming number of civilian casualties.”