The U.S. should consider forcing major American companies such as General Electric and Exxon Mobil to suspend business in or pull out of Russia if President Vladimir Putin attempts to take more territory from Ukraine or other neighboring nations, said Senator John McCain of Arizona.

“I know that that’s a tough call and I know that we don’t want to hurt our own economy, but what are the consequences of Vladimir Putin just being able to act?” McCain, a Republican who advocates military assistance for the Ukraine, said in an interview for Bloomberg Television’s “Political Capital with Al Hunt” this weekend.

Such a move likely would come through formal sanctions rather than political pressure on individual corporations, McCain said, and “would only be considered” if Putin “went much further.”

In addition to GE and Exxon-Mobil Corp., the companies with the largest business interest in Russia include Ford Motor Co., General Motors Co., Citigroup Inc., JPMorgan Chase & Co., and PepsiCo Inc.

Putin, who annexed Crimea from Ukraine earlier this month, has amassed tens of thousands of troops along the border, which McCain says indicates Russia may strike soon.

“If you’d asked me three or four days ago, I’d have said I believe not — now I’m not sure,” he said. “You don’t keep troops massed on the border of a country for no reason.”