US President Barack Obama has warned White House contenders to avoid raising tensions, a day after a rally by Donald Trump was called off amid clashes.

Obama said candidates should not resort to "insults" and "certainly not violence against other Americans".

Trump, who leads the race for the Republican nomination, cancelled his Chicago rally after fighting broke out between his supporters and protesters.

His rivals and others have accused him of using inflammatory rhetoric.

Obama, who will be standing down next January following November's presidential election, was speaking at a Democratic Party fundraiser in Dallas on Saturday.

He said: "What the folks who are running for office should be focused on is how we can make it even better - not insults and schoolyard taunts and manufacturing facts, not divisiveness along the lines of race and faith."

(BBC)