US election 2016: Hillary Clinton and Bernie Sanders trade primary victories in Kentucky and Oregon

While Ms Clinton looked to have eked out a slim victory in the Bluegrass State, the Sanders campaign won comfortably in the northwest

Hillary Clinton campaigning in Kentucky (Getty)

The contentious Democratic presidential race remained unresolved on Tuesday night as frontrunner Hillary Clinton edged past her dogged challenger, Bernie Sanders, in the Kentucky primary, while the progressive Vermont Senator secured a more comfortable victory in Oregon.

Mr Sanders has now claimed 19 states to Ms Clinton's 24. But Democratic delegates are distributed proportionately in every primary, and Ms Clinton’s wins in big states such as New York, Texas, Florida and Pennsylvania have helped her to maintain a commanding lead in the increasingly divisive contest. The former Secretary of State also holds significant poll advantages in the two largest remaining states, New Jersey and California, which both go to the polls on 7 June, the last day of primary season.

Kentucky is worth 61 delegates overall, and Oregon 73. Mr Sanders appeared to have a seven-point triumph on his hands in Oregon, compared to Ms Clinton's wafer-thin win in the Bluegrass State, which means the Vermont Senator will likely come away from last night's contests with the heavier delegate haul. But Ms Clinton is edging ever closer to the 2,383 delegate majority she needs to clinch the Democratic presidential nomination.

Despite the adverse arithmetic, Mr Sanders, who became a Democrat last year after a lengthy career as an independent, has vowed to fight on at least as far as the final primaries next month – and even to contest the party’s convention in Philadelphia in July. Speaking at a campaign rally in Carson, California yesterday, he said: "Before we will have the opportunity to defeat Donald Trump, we're going to have to defeat Secretary Clinton."

With Mr Trump having run unopposed in Oregon, the only GOP primary of the night, Republicans are resigned – if not uniformly agreeable – to the billionaire real estate mogul being their nominee. Over the weekend, it was instead the Democrats’ turn to tackle dissent in their ranks. The party’s Nevada convention was disrupted by Sanders supporters, who threw chairs and threatened the state’s party chairwoman, angry at the process of awarding delegates, which they saw as biased towards Ms Clinton.

Nevada Senator Harry Reid, a Democrat and the Senate minority leader, urged Mr Sanders to condemn his supporters’ actions, while Democratic National Committee chairwoman Debbie Wasserman Schultz said there was “no excuse for what happened”. Mr Sanders subsequently condemned the unrest, but declined to apologise, saying claims that his campaign had a “penchant for violence” were “nonsense”. In a statement, he also suggested the Nevada Democratic leadership had "used its power to prevent a fair and transparent process."