President Joe Biden on Tuesday acknowledged the likelihood that U.S. and allied sanctions on Russia in retaliation for an invasion of Ukraine would have significant blowback on the American economy, including possible price hikes and disruption to the nation’s energy supply.

“The American people understand that defending democracy and liberty is never without cost,” Biden said in remarks at the White House about the ongoing crisis. “I will not pretend this will be painless.”

He said the administration was working proactively to try to preempt supply issues by working with energy producers and shippers on contingency plans, and said he would work with Congress on unspecified “additional measures to protect consumers and address the impact of prices at the pump.”

Biden also said Tuesday that the U.S. has “not yet verified” Russia’s claim that some of its forces have withdrawn from the Ukraine border. He said an invasion of Ukraine remains a distinct possibility.