Donald Trump's anti-Mexican comments and his rant against Republican heavyweight Sen. John McCain, R-Ariz., have led the Des Moines Register to call on the television personality to drop out of the 2016 White House race.

During his campaign, the real estate mogul has been "more focused on promoting himself ... than on addressing the problems facing the nation," the newspaper said in an editorial. The Register, Iowa's largest publication, is widely read in the state that traditionally holds the crucial first-in-the-nation caucuses.

"If he were merely a self-absorbed, B-list celebrity, his unchecked ego could be tolerated as a source of mild amusement," the Register's editorial board wrote. "But he now wants to become president, which means that he aspires to be the leader of the free world and the keeper of our nuclear launch codes. That is problematic, because Trump, by every indication, seems wholly unqualified to sit in the White House."

In a lengthy statement released on Tuesday, Trump shot back by calling the Register "sophomoric" and pointing out that a recent poll showed him leading the crowded GOP field of candidates, according to Politico.

"As one of the most liberal newspapers in the United States, the poll results were just too much for (editors) to bear. ... They will do anything for a headline, and this poorly written 'non-endorsement' got them some desperately needed ink," Trump wrote. "They never captured the energy of each event and it is a constant battle with them by my representatives to get an accurate count of the large crowds I draw."

Nevertheless, Trump on Tuesday received even more bad press as the Associated Press challenged his dismissive remarks about McCain's record on veterans' issues.

The Arizona senator was instrumental in a landmark law approved last year to overhaul the scandal-plagued Department of Veterans Affairs, and he aggressively supported legislation aimed at reducing a suicide epidemic among military veterans that claims the lives of an estimated 22 people every day, the newswire detailed.

Trump, who never served in the armed forces, had claimed that the former Navy pilot and prisoner of war had "done nothing to help the vets" who were "living in hell."