Facing no active opposition, Donald Trump on Wednesday cruised to victory in the Washington state primary and was just one step away from clinching the Republican presidential nomination to set up a likely clash with Hillary Clinton in the November polls.
The win in Washington state, where he received 76.2 per cent of the total votes polled, brought him less than 10 delegates shy of clinching the nomination.
The victory -- winning at least 40 of Washington's delegates -- means 69-year-old Trump now has 1,229 of the 1,237 delegates he needs to clinch the GOP nomination, according to CNN estimates.
Four more Washington delegates are still to be decided, potentially boosting the real estate tycoon's total even higher.
In the primary, Trump garnered over 76 per cent of the vote as Texas Senator Ted Cruz and Ohio Governor John Kasich each earned 10 per cent of the vote, while retired neurosurgeon Ben Carson earned 4 per cent of the vote.
Washington did not have enough delegates to put him over the line. However, its results do, however, leave him inches short of it with a slate of contests on June 7 in California, New Jersey, New Mexico, Montana and South Dakota sure to seal the deal.
"Thank You Washington," Trump tweeted after major news channels projected his win in the state.
Trump's victory, however, was overshadowed by the clashes between anti-Trump protesters and police outside his event in Albuquerque, New Mexico.
Protesters broke through police barricades, lit fires and threw rocks at the city's convention centre, smashing one door.
Some taunted police and jumped on police vehicles. Officers in riot gear and on police horses moved the protesters away from the convention centre as anti-Trump chants rang through the city's streets.
Trump is the only Republican candidate left in the race to the White House from the Republican party, which was crowded with as many as 17 candidates at the start of the primary season early this year.
On the other hand, the race to the White House in the Democratic party which had just three candidates at the start of this year, is still open.
While 68-year-old Clinton is likely to clinch the nomination because of the lead she has in delegate count, her opponent Senator Bernie Sanders from Vermont has refused to call off the race till the last vote in the primary election is cast.
Campaigning in California, Sanders told his supporters that he would not let Trump become the US President.
Sanders' campaign on Tuesday released a new television spot that will run in California ahead of the state's June 7 primary election.