White House economic adviser Cecilia Rouse said on Monday that the biggest U.S. economic risk from Russia's invasion of Ukraine is from higher gasoline prices, and the depth of the impact will depend on the length of the conflict.

Rouse, who chairs the Council of Economic Advisers, told a Politico online event that President Joe Biden was working with allies and using every available tool to ease the impact of higher fuel prices, including consideration of releasing oil from the U.S. strategic petroleum reserve.

"You know, the economic risks will hinge on the length of this war. And the more quickly it is resolved, the smaller the impact. The longer it goes on the deeper the uncertainty," Rouse said.