Los Angeles:
Presumptive Republican nominee Mitt Romney won primary ballots in Oregon and Nebraska on Tuesday, partial results showed, moving him a step closer to winning his party's formal White House nomination.
Mr Romney won 73 per cent of the vote in Oregon against 12.2 per cent for Ron Paul, who suspended active campaigning this week, and 5.7 per cent for Newt Gingrich, according to results from nearly two thirds of precincts.
In Nebraska the former Massachusetts governor had some 70.9 per cent of votes compared to 9.9 per cent for Paul and 5.2 per cent for former House Speaker Gingrich, according to nearly complete results.
Even if he won all of Oregon's 25 delegates and Nebraska's 32 -- from a non-binding poll -- he would not be able to reach the 1,144 needed to clinch the Republican nomination.
Before Tuesday's two latest primaries -- which have become mostly academic since the other main candidates dropped out of the race - Mr Romney had 963 delegates, 181 short of the winning tally, CBS reported.
Mr Romney has turned his fire onto President Barack Obama, his rival for the White House in November elections, since his main rival conservative Catholic Rick Santorum withdrew from the race in April.
Earlier on Tuesday Mr Romney won the backing -- albeit in unorthodox fashion -- of former president George W. Bush to be White House nominee, to be chosen by Republicans at their August convention in Tampa, Florida.
"I'm for Mitt Romney," Mr Bush said, as elevator doors were closing on him, according to an ABC television blog report. Mr Bush is not due to campaign for Mr Romney, ABC said.