The United States has a senior diplomat, Chris Stevens, in the Libyan rebel stronghold Benghazi to liaise with the TNC, but it has not recognized the rebel movement as the country’s legitimate government, as have some NATO allies.

A State Department spokesman said the aid commitment does not necessarily mean the United States is closer to recognizing the TNC and shows there are ways the United States can boost the opposition short of such a step.

Clinton meanwhile underscored U.S. concern about mounting political violence in Syria, where news reports say more than 20 protesters have been killed by security forces in the central city of Homs.

She said the United States strongly condemns any use of violence by either side in the ongoing confrontation, and is particularly worried about the situation in Homs, where it is difficult to ascertain facts because of curbs on journalists.

"The Syrian government must allow free movement and free access," said the secretary of state. "It must stop the arbitrary arrests, detentions and torture of prisoners. And it must cease the violence and begin a serious political process through concrete actions to demonstrate its responsiveness to the legitimate issues that have been raised by the Syrian people seeking substantial and lasting reform."

The State Department expressed skepticism Tuesday at the Damascus government’s move to end 48 years of emergency rule, noting that the pending repeal is coupled with new legislation to curb demonstrations.