2:45 PM PST -- Senator and former Presidential hopeful John McCain just announced he's withdrawn his support for Trump.
Donald Trump isn't backing down from his bid for Prez ... even though he's taking major heat from the heavy hitters in the Republican Party asking him to call it quits.
Trump spoke with The Washington Post Saturday, saying, "I'd never withdraw. I've never withdrawn in my life." He continues, "No, I'm not quitting. I have tremendous support."
Trump told The Wall Street Journal there is "zero chance I quit."
Trumps defiance comes on the heels of heavy criticism from Republican big wigs like Senator John Thune and even his running mate Governor Mike Pence who said he was "offended" by Donald's remarks.