WASHINGTON (AP) -- Two advisers to Republican presidential candidate Newt Gingrich say he will formally end is campaign next Tuesday and will likely to endorse Mitt Romney.

Gingrich had pinned his hopes on a surprise showing in Delaware but fell short.

He had been hinting in recent days that his campaign was nearing an end. His decision to officially shut down the effort comes as Romney has a lock on the GOP nomination.

Gingrich's advisers spoke to The Associated Press on the condition of anonymity given the sensitivity of the situation.