The Obama administration is not indicating whether it has a strategy in the event that the regime of Syrian President Bashar al-Assad collapses, even as rebels have gotten closer to toppling it, according to the Washington Free Beacon.

A State Department official did not say whether the administration has outlined a specific plan should Assad be ousted, but said that the United States is working with the Saudis and other Arab states in the region to train and equip opposition forces to fight the Islamic State (ISIS or ISIL).

The official added that the U.S.-trained force will also "protect the United States, its friends and allies, and the Syrian people from the threats posed by terrorists in Syria; and promote the conditions for a negotiated settlement to end the conflict in Syria."

U.S. airstrikes against the Islamic State in Syria will continue as the train-and-equip program progresses, the official added.

Rebel groups have advanced in both the north and the south of the country, and a new rebel coalition backed by Saudi Arabia, Turkey and Qatar has taken control of a northern province and is advancing toward strongholds in the country's south, the Beacon said.

Michael Rubin, resident scholar at the American Enterprise Institute and a former Pentagon adviser on the Middle East during the George W. Bush administration, told the Beacon that if Assad is deposed, "the most radical, most violent, and most determined forces are going to fill the void."

"The strategies that Obama now embraces might have worked fine when the malignancy in Syria was at Stage 1, but it has now metastasized to Stage IV," he said, according to the Free Beacon. "You can't treat that sort of ailment with an aspirin."

Meanwhile, the State Department has declined to discuss the status of the Assad regime.

"I don't have an analysis of the internal dynamics of the Syrian Government to offer," spokesman Jeff Rathke said at a press briefing on Monday, according to the Beacon. "Clearly, Assad has lost his legitimacy. We've said that a number of times. But I don't have an analysis of their — of the regime's longevity."

One expert said recently, however, that as the Assad regime weakens, the administration must be prepared with a rigorous response.

"The near-term requirements for putting Syria on a path to stability and legitimacy center on regional ground forces (in conjunction with coalition air forces) sweeping ISIL from central and eastern Syria; permitting a real government for all Syrians to emerge in free Syria; putting 'train and equip' on steroids by building a Syrian National Stabilization Force; and stopping the Assad regime from visiting mass terror on civilian populations," said Frederic Hof, resident senior fellow at the Atlantic Council and a former adviser on Syria for the Obama administration.

"None of it requires U.S. boots on the ground. All of it — every bit of it — requires sustained U.S. diplomatic effort and leadership."

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