The right-leaning Wall Street Journal editorial board, long a critic of Donald Trump, said it's time for the Republican nominee to drastically change his campaign or bow out of the race.

On Sunday, the Journal said that Trump's biggest backers in the GOP "face a moment of truth."

"If they can't get Mr. Trump to change his act by Labor Day, the GOP will have no choice but to write off the nominee as hopeless and focus on salvaging the Senate and House and other down-ballot races," the paper said. "As for Mr. Trump, he needs to stop blaming everyone else and decide if he wants to behave like someone who wants to be president — or turn the nomination over to [vice presidential candidate] Mike Pence."

Trump has fallen under intense media scrutiny in recent weeks amid a series of provocative comments and falling poll numbers against Democratic rival Hillary Clinton.

Trump continues drawing large crowds to campaign rallies across the country and has delivered some scripted policy speeches. But some within the GOP, including Maine Sen. Susan Collins, have accused Trump of begin unpresidential and said they will not support him.

Over the weekend, Trump blamed most of his campaign woes on a dishonest national news media.

"'Stay on message' is the chant I always do — trade, jobs, military, vets, 2nd A, repeal [Obamacare], borders, etc — but media misrepresents," he said in one tweet.