The United States has declared a Syrian Jihadist force as a terrorist organization, while Western powers gathered in Morocco to push international support for Syria's new opposition coalition.
The State Department designated Jabhat al-Nusra as a terror group on Tuesday, saying that it serves as an alias of al-Qaida in Iraq as it attempts to infiltrate the Syrian conflict.
The U.S. Treasury sanctioned two senior leaders of the al-Nusra front for acting on behalf of al-Qaida in Iraq. The department also announced sanctions against two armed militia groups that back Syrian President Bashar al-Assad.
The undersecretary for terrorism and financial intelligence, David Cohen, said the United States "will target the pro-Assad militias" just as it targets "the terrorists who falsely cloak themselves in the flag of the legitimate opposition."
Listing an entity as a terror organization bars Americans from doing business with the group.
Jabhat al-Nusra has claimed responsibility for suicide bombings in Syria.
Friends of Syria meeting
Officials from European Union nations and the United States will gather Wednesday in Morocco for a Friends of Syria meeting aimed at supporting the rebels opposed to President Bashar al-Assad.
U.S. Secretary of State Hillary Clinton is not taking part in the meeting, after canceling her Middle East trip because of an illness.
France, Britain and members of the Gulf Cooperation Council have recognized the opposition coalition as the representative of the Syrian people. Despite broad support for the ouster of Assad, the United States and some European nations have been hesitant to fully recognize the coalition.
British Foreign Secretary William Hague expressed hope Monday that more nations will back the coalition, after EU foreign ministers held talks with new Syrian opposition leader Mouaz al-Khatib.
Russia is not taking part in the talks Wednesday. Moscow objects to any outside interference in a Syrian transition process, saying any decisions about political reforms should be made by Syrians themselves.
Meanwhile, U.S. Defense Secretary Leon Panetta says there is no new indication of any "aggressive steps" by the Syrian government to use chemical weapons.
"We continue to monitor it very closely, and we continue to make clear to them that they should not under any means make use of these chemical weapons against their own population, that that would produce serious consequences," Panetta said.
Panetta's comments Tuesday follow earlier warnings from U.S. President Barack Obama and other Western leaders that a chemical weapons attack would draw a response against Syria.
Also Tuesday, the United Nations refugee agency said the number of Syrian refugees registered or waiting to be registered now stands at more than 500,000. The agency said that includes the latest count from Lebanon, Jordan, Iraq, turkey and North Africa.
Fighting between rebels and government forces has already claimed more than 40,000 lives, with no let-up in sight.