Donald Trump rolled up victories in five more states, amassing a north-eastern sweep that gives the Republican front-runner important momentum in his push for the presidential nomination even if his pathway has little room for error.

Donald Trump has hit out at a collaboration between Ted Cruz and John Kasich aimed at unifying the anti-Trump vote in some remaining primaries.

Donald Trump's Republican rivals have announced shock plans to co-ordinate primary strategies in upcoming states to deprive the front-runner of the delegates he needs to win the party nomination.

Painstaking organisation and in-person campaigning paid off again for Ted Cruz. He won all 14 delegates at the Republican Party convention in Wyoming.

Republican presidential front-runner Donald Trump is calling on rival John Kasich to get out of the White House race, arguing that the Ohio governor should not be allowed to collect future delegates because the nomination is already beyond his grasp.

A frustrated Donald Trump stepped up his presidential campaign after a rough week and found himself on the defensive just two days before the closely watched primary in Wisconsin.

Protesters blocked a main road leading to the Phoenix suburb where Republican presidential front-runner Donald Trump staged a campaign rally days ahead of the Arizona primary.

Front-runner Donald Trump tried to prove no perceived misstep can derail his march to the Republican presidential nomination.

Republican front-runner Donald Trump has vowed to continue his abrasive presidential campaign rhetoric, rejecting any responsibility for violence at his rallies and defending supporters accused of attacking protesters.

Republican presidential candidates Marco Rubio and John Kasich have suggested they may not support Donald Trump if he becomes the Republican nominee, as violence at the front-runner's rallies deepened the party's chaotic chasm.

Donald Trump has called for Republicans to rally behind his presidential candidacy after he cruised to primary victories in three more states.

Socialist Bernie Sanders has breathed new life into his long-shot White House bid with a crucial win in Michigan's presidential primary, chipping away at Hillary Clinton's dominance in the Democratic race.

Ohio Governor John Kasich has praised the mostly peaceful protests following the acquittal of a white patrolman charged in the deaths of two unarmed black motorists in a barrage of police gunfire.

Three women who survived a decade of captivity in an Ohio house before being freed have received bravery awards.

A condemned child killer’s execution has been delayed so officials can study the feasibility of the man’s request to donate his organs.