DOHA, Qatar -- Political opponents of Syrian President Bashar Assad established a new organization Sunday and elected an activist Muslim cleric to lead it, a move that could open the spigot of international humanitarian aid to Syria. But questions remained on when and if a step-up of military aid will follow.

The United States, which had publicly demanded the reform, welcomed the “vitally important step” and once again demanded that Assad step down.

“This offers a credible, cohesive leadership, reflective of Syrians inside your country and outside,” Beth Jones, the acting assistant secretary of state for Near Eastern affairs, said, referring to the newly created the Syrian National Coalition. “We want to work with and cooperate fully with your new organization, because we share the goal of Bashar al Assad leaving power.”

“Lazim yetanahi”– “He must step down” – she said in Arabic, but she did not explain how that was to come about. The United States has refused to send military aid, apparently fearing it will lead Assad’s main allies, Russia and Iran, to escalate their support. Instead, U.S. officials have called for a “political solution,” without defining that precisely.

The group’s new leader, Moaz al Khatib, who had served as the imam at the historic Umayyad mosque in Damascus until he left the Syrian capital in July, is relatively little known abroad but has a reputation as a man of moderate views and an open advocate for avoiding a descent from the raging civil war into an even worse sectarian conflict.

In his first remarks as head of the new organization, Khatib said Syrians “need humanitarian aid and to stop the bloodshed.” He avoided calling for arming the Syrian resistance.

In an interview with Reuters last July, Khatib said that the country’s Alawite minority, which the Assad dictatorship has placed in leading positions in the security and government apparatus, “are even more oppressed because the state took them and used them, putting them in a confrontation with the rest.”

Khatib is said to have the support of municipal councils in rebel-held areas. He also has the backing of the Muslim Brotherhood, a Sunni Islamist party that is outlawed in Syria. Muslim Brotherhood affiliates have come to dominate elected governments in Egypt and Tunisia after longtime dictators were toppled in those countries.

Riad Seif, a Syrian businessman who served in the Syrian Parliament and then spent several terms in jail as a political dissident, was the principal organizer of the new initiative and was elected a deputy president of the new group. Suhair al Atassi, a female anti-Assad activist, was elected as a second vice president.

Jones, the U.S. official, urged the new organization, whose full name is the Syrian National Coalition for the Forces of the Opposition and the Revolution, to set up a technical group with which the international community can “work quickly.” She said she was sending a top level official to London to attend an emergency aid meeting that the British government has called for Friday.

In late October, Secretary of State Hillary Clinton publicly called for the new group to supplant the Syrian National Council, which had been the biggest exile umbrella group. Founded little over a year ago, the SNC has been widely criticized for infighting, lackluster leadership, and a failure to raise sufficient funds or to establish close links with fighting groups inside Syria.