Trump unfit to serve as president, declares Obama

Launching the harshest comment till date on Donald Trump, U.S. President Barack Obama declared the Republican nominee as entirely unfit to serve in the top post.

This comment in the White House East Room came on Tuesday after Trump's criticism of the family of a slain Muslim U.S. soldier.

"The Republican nominee is unfit to serve as president.. He keeps on proving it," CNN quoted Obama as saying at a White House news conference.

Describing his feelings about Trump as unprecedented, Obama recalled disagreements with previous GOP presidential nominees Senator John McCain and Mitt Romney.

"The notion that he would attack a Gold Star family that made such extraordinary sacrifices on behalf of our country, the fact that he doesn't appear to have basic knowledge of critical issues in Europe, the Middle East, in Asia, means that he's woefully unprepared to do this job," he said.

Obama was speaking alongside Singapore Prime Minister Lee Hsien Loong in the White House East Room.

He pointed out there are now weekly episodes in which even Republican party leaders distance themselves from Trump.

"There has to be a point at which you say, 'Enough,'" he added.

He also placed responsibility for Trump's statements on his fellow Republicans, many of whom denounced his statements on the slain soldier's family but didn't withdraw their support.

The Republican presidential nominee and the family of the slain soldier have been locked in an bitter dispute over Muslims in America and the nature of patriotic sacrifice, after Khizir Khan, father of the soldier killed in a suicide bombing in Iraq, said that Trump had sacrificed nothing.

Khan made the statement at last week's Democratic National Convention following which the Republican nominee claimed he had been viciously attacked.