Frustrated with the divisions in the Syrian opposition and its Syrian National Council, Washington is pushing for a wider political force, more representative of the people fighting on the ground and able to curb an Islamist 'hijack' of the revolution.
During her Balkan tour this week, US Secretary of State Hillary Clinton spelled out the frustration that the United States, Europe, the Arab League and many Syrians feel towards the SNC umbrella opposition group, which has been unable to form a united front to "resist the violence" of the Syrian regime.
In Zagreb, Clinton called for a new, "larger" opposition, which would include those "from inside Syria."
"There has to be a representation of those who are on the front line fighting and dying today to obtain their freedom," Clinton said.
Clinton's public disapproval of the SNC comes after months of warnings in private.
She insisted that it "can no longer be viewed as the visible leader of the opposition."
As violence escalates throughout Syria, Washington has accused the SNC of failing to unite the resistance against the regime of President Bashar al-Assad beyond a small group of Syrian exiles, some of whom have not set foot in their homeland "for 20, 30 or 40 years," Clinton said.
The opposition remains deeply divided between the groups in Syria and those outside the country. And the SNC, long considered as a "legitimate interlocutor" for the international community, has failed to prove its credibility.
The world powers who call for Assad's ouster have been urging the opposition for months to unite and form a transitional government representing all communities in Syria.
Washington has long insisted that the minorities -- like the Alawites of whom Assad himself is a member and which make up 10 percent of the population as well as the Kurdish and Christian communities which account for about five percent -- must not be forgotten.
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Washington recalled Turkish concern about a possible secession by the Kurds in Syria and fears of a rise of Sunni extremists in the multi-faith country.
Clinton warned of "disturbing reports of extremists going into Syria and attempting to take over what has been a legitimate revolution against a repressive regime for their own purposes."
The goal of the US and its European and Arab partners is now fourfold: to see a united, plural, democratic opposition emerge which will offer an alternative to jihadists' threats in Syria; then to unify political efforts in the country, including in already liberated zones.
Such an opposition should also show to Russia and China that there is an alternative to the chaos they fear. And finally, it should present to the international community a credible plan for a political transition.
Washington has pinned its hopes on a meeting of hundreds of Syrians opposed to Assad's regime, due to be held under the auspices of the Arab League next week in Doha.
Clinton said the US has "recommended names and organisations that we believe should be included in any leadership structure" to be invited for a meeting in Qatar.
But only Syrians can pick future leaders of Syria, warned a US official who did not want to be named.
"Our goal is to ensure that some of the superb individuals inside Syria who have been calling for a democratic Syria get a chance to be heard," the official told AFP.
Following Clinton's call for Syria's opposition to reject extremism, the head of the SNC said the West and its partners were to blame for rising radicalisation.
"The international community is responsible, through its lack of support for the Syrian people, for the growth of extremism in Syria," SNC director Abdel Basset Saida told AFP.
"The international community should criticise itself, and ask itself: What did it give the Syrian people? How has it helped the Syrians to stop the regime's crazy killing?" he said.