US politicians have voiced disgust and alarm after a rally crowd responded to Donald Trump’s racist attacks on congresswoman Ilhan Omar with chants of “send her back”.

Democrats warned the president was “fuelling and feeding off hate” and “stoking the most despicable and disturbing currents in our society” by vilifying Ms Omar, a Somali refugee who arrived in the US as a child nearly three decades ago.

Senator Bernie Sanders said Mr Trump was “the most dangerous president in the history of our country,” while fellow 2020 election hopeful Elizabeth Warren called for him to face impeachment.

On Thursday, the president chided his supporters who chanted the statement at the rally, joining widespread criticism of the campaign crowd’s cry after fellow Republicans warned it could hurt the GOP in next year’s elections.

In a week that has corkscrewed daily with hostile exchanges over race and love of country, Mr Trump also claimed he had tried to stop the chant at a reelection event Wednesday night in North Carolina.

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“I started speaking really quickly,” he told reporters. “I was not happy with it. I disagree with it.”

However, video shows the crowd’s “send her back” shouts resounded for 13 seconds as Mr Trump made no attempt to interrupt them. He paused in his speech and surveyed the scene, taking in the uproar.

Ms Omar responded on Thursday, telling reporters: “This is what this president and his supporters have turned our country” into, she said as she walked outside the US Capitol.

“This is not about me," she added. "This is about fighting about what this country truly should be and what it deserves to be.”

Additional reporting by AP. Please allow the live blog to load.