Mitt Romney won the Republican presidential primaries in Nebraska and Oregon, the Associated Press projected Tuesday night, continuing his march toward the GOP nomination.

Romney's wins came a day after Ron Paul, his lone remaining rival, announced the effective halt of his presidential bid. Paul said Monday he will not campaign in any new primary states, but will continue to organize at conventions in states that have already voted.

The presumptive nominee has yet to clinch the delegates necessary to seal the nomination. Romney will be able to do that May 29, when Texas votes.