'I'm just the messenger'

Republican presidential candidate Donald Trump refused to take responsibility yesterday for clashes that have erupted at his campaign events, saying he was not inciting violence but giving voice to the anger of his supporters.

The real estate tycoon used a round of television appearances to beat back furious criticism from Republican rivals and Democrats alike that he was encouraging discord with divisive language disparaging Muslims and immigrants.

"I don't accept responsibility. I do not condone violence in any shape," Trump said on NBC's "Meet the Press."

The tension at his rallies, Trump said, came from people being "sick and tired" of American leadership that has cost them jobs through international trade deals, failed to defeat Islamic State terrorism and treats military veterans poorly.

"The people are angry at that - they're not angry about something I'm saying. I'm just the messenger," Trump said.

On Saturday, Trump suffered heavy defeats in Republican caucuses in Washington DC and Wyoming.

The disturbances at his campaigns erupted days before the next five presidential nominating contests on Tuesday, which could cement the New York billionaire's lead over Republican rivals US Senators Ted Cruz and Marco Rubio and John Kasich.

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