WASHINGTON (Reuters) - U.S. Senator John McCain said on Monday that a vote by the U.S. Congress against President Obama's proposal for using military force in Syria would be catastrophic.

"If the Congress were to reject a resolution like this after the president of the United States has already committed to action, the consequences would be catastrophic," McCain told reporters after a meeting with the president at the White House. McCain, a Republican, said he was encouraged by the meeting but that the administration still had a "long way to go" to get the resolution passed.

(Reporting by Susan Cornwell; Editing by Eric Beech)