"I am very concerned about maintaining momentum," The New York Times quoted Votel as telling reporters. "It could be that we take on a larger burden ourselves."
On Friday, US Department of Defense spokesman Jeff Davis said the Kurdish-dominated Syrian Democratic Forces (SDF) was close to fully isolating Raqqa as part of the operation to liberate the city from the Daesh.
But Turkey, which views the Kurdish People's Protection Units (YPG) as an arm of the banned Kurdistan Workers' Party (PKK), has opposed US efforts to directly arm the Kurdish forces.
Votel said one option to maintain momentum against the Daesh would be for the Pentagon to "bring more of our assets to bear" instead of relying on partners on the ground, or bringing other forces to the fight for Raqqa.
However, he would not necessarily advocate for large numbers of Special Operations troops.
The United States currently has about 500 Special Operations forces on the ground in Syria.
The newspaper reported that US troops in Syria could expand their advise and assist mission to including firing artillery and mortars in support of local forces, similar to the role US troops play in Iraq.
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