Democratic presidential candidates joined the White House in rebuking Donald Trump on Friday, for failing to challenge a questioner who claimed President, Barack Obama was a Muslim and not a US citizen.
The businessman, who is the frontrunner for the Republican nomination for president, has been strongly criticised by two of his Republican rivals.
South Carolina Senator, Lindsey Graham strongly criticised the businessman Donald Trump, saying Trump behaved inappropriately and should apologise.
The criticism has been increasing since a man at Trump's rally in New Hampshire on Thursday, claimed Mr Obama was a Muslim and "not even an American" and Trump let it go unchallenged.
The supporter also said, "We have a problem in this country - it's called Muslims."
Hillary Clinton said Trump let it go unchallenged and within a few hours described Trump’s attitude as "hateful rhetoric" that was "disturbing and wrong".
His campaign team said he was pulling out of the Heritage Foundation because of a "significant business transaction" that needed his attention.
New Jersey Governor, Chris Christie said leaders have an "obligation" to correct such statements.
Christie added, "If somebody at one of my town hall meetings said that, I would correct them and I would say, 'The president's a Christian and he was born in this country. Those two things are self-evident."
White House spokesman, Josh Earnest said, "Mr Trump isn't the first Republican politician to countenance these views to gain votes."
People on social media criticised Trump's attitude also.
— Amanda Rae Lombardi (@manndaraee) 19 Eylül 2015