Romney vows to press ahead in nomination race

BOSTON (Reuters) - Republican presidential hopeful Mitt Romney vowed to press ahead with his campaign for his party's nomination despite losing several key primary contests on Tuesday to rivals John McCain and Mike Huckabee.

"One thing that's clear is this campaign is going on," the former Massachusetts governor told supporters. "It's not all done tonight. We're going to keep on battling."

(Reporting by Jeremy Pelofsky and Rob Doherty, editing by Frances Kerry)