The Republican presidential nominee is under fire from his party and the Democrats after he was caught on tape boasting about sexually harassing women.
US President Barack Obama said on Tuesday that the Republican presidential nominee's comments on a 2005 videotape would disqualify him from even a job at a convenience store.
In the controversial tape, caught on a hot microphone, Donald Trump is heard bragging about groping and kissing women without their consent. Trump has been known for controversial comments throughout his campaign but his comments have become the red line for both Democrats and Republicans.
"Now you find a situation in which the guy says stuff that nobody would find tolerable if they were applying for a job at 7-Eleven," Obama told a campaign rally for Democratic presidential nominee Hillary Clinton in Greensboro, North Carolina.
Obama also criticised some Republicans who have condemned the remarks but are still backing the New York businessman.
"The fact that now you've got people saying: 'We strongly disagree, we really disapprove ... but we're still endorsing him.' They still think he should be president, that doesn't make sense to me," Obama said.
Earlier on Tuesday, White House spokesperson Josh Earnest said the remarks in the recording amounted to sexual assault.
Obama also took aim at Trump's business credentials, referring to a New York Times report that showed he claimed a nearly billion dollar loss in one year on his taxes in the 1990s.
"They say the house always wins," Obama quipped about Trump, who was a casino developer at the time. "I don't know how that happens."
Trump said during Sunday night's presidential debate he was embarrassed by the video, but dismissed it as "locker room talk".
Trump lashed out at US House Speaker Paul Ryan and other "disloyal" Republicans on Tuesday. He vowed to campaign in whatever style he wants now that the party establishment has largely abandoned him.
"It is so nice that the shackles have been taken off me and I can now fight for America the way I want to," Trump said on Twitter. He added he would engage Democratic rival Hillary Clinton on his own terms.
In a barrage of stinging Twitter posts, Trump condemned the Republicans who backed away from his White House run.
Disloyal R's are far more difficult than Crooked Hillary. They come at you from all sides. They dont know how to win - I will teach them!— Donald J. Trump (@realDonaldTrump) October 11, 2016
Ryan, the top Republican in Congress, told party lawmakers on Monday he was breaking with Trump and would not campaign for him. Ryan all but conceded Clinton would win the presidency. The move angered some Trump supporters, although Ryan said he would not withdraw his endorsement of the New York businessman.
Trump also took aim at US Senator John McCain of Arizona, the 2008 Republican presidential nominee, who said on Saturday that he could not vote for Trump.
The very foul mouthed Sen. John McCain begged for my support during his primary (I gave, he won), then dropped me over locker room remarks!— Donald J. Trump (@realDonaldTrump) October 11, 2016
There was no immediate reaction from McCain.
Many Republicans worry that Trump's abrasive campaign could hurt their chances of holding the majority in the House of Representatives and Senate in next month's election. Republicans worry Trump's words will inflict long-term damage on the party.
A Reuters/Ipsos poll of likely voters released on Tuesday found 58 percent of Republicans wanted Trump to stay on their party ticket and 68 percent said the Republican leadership should stand by him.
The poll, which was conducted after the second presidential debate on Sunday, showed Clinton's lead over Trump widening to 8 points from 5 points last week.