Obama calls on GOP leaders to un-endorse Trump: 'There has to be a point where you say enough'

President Barack Obama called on Republican leaders to withdraw their endorsements of Donald Trump following his criticism of the father of a slain Muslim American soldier.

In a press conference at the White House on Tuesday, Obama said it was not enough for Republicans like House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell to condemn the Republican presidential nominee's controversial statements, including his critique of Khizr Khan, who denounced Trump's proposal to bar all Muslims from entering the US.

"The question I think that they have to ask themselves is if you are repeatedly having to say, in very strong terms, that what he has said is unacceptable, why are you endorsing him? What does this say about your party that this is your standard-bearer?" Obama said.

The president continued: "This isn't a situation where you have an episodic gaffe. This is daily and weekly where they are distancing themselves from statements he's making. There has to be a point at which you say 'This isn't someone I can support as president of the United States. Even if he purports to be a member of your party. The fact that that has not happened makes some of them ring hollow."

Obama said that Trump's comments about Khan showed why the real-estate magnate was "unfit" to serve as president, adding that Obama never doubted former Republican nominees Gov. Mitt Romney and Sen. John McCain's fitness to occupy the office, despite policy differences.

"There have been Republican presidents with whom I disagreement that I didn't have a doubt they could serve as president," Obama said.

He added:

"I thought I was right and Mitt Romney and John McCain were wrong on certain policy issues, but I never thought that they couldn't do the job. And had they won, I would've been disappointed, but I would've said to all Americans - this is our president and I know they're going to abide by certain norms and rules and common sense and observe basic decency. Will have enough knowledge of economic policy and foreign policy and our constitutional issues and rule of law that our government will work, and we'll compete in four years to win an election. But that's not the situation here. There has to come a point at which you say enough."