Republicans are in an uproar after presidential candidate Donald Trump came close to placing responsibility for the Sept. 11, 2001, terrorist attacks on former President George W. Bush on Friday.

“When you talk about George Bush, I mean, say what you want, the World Trade Center came down during his time,” Trump told Bloomberg TV.

Bloomberg anchor Stephanie Ruhle, apparently taken aback by the comment, said, "Hold on, you can't blame George Bush for that.”

But the billionaire developer, the front-runner for the Republican primary nomination, restated his comments.

“He was president, OK?” Trump said. “The World Trade Center came down during his reign.”

Bush’s brother, Jeb, who is also running for the party’s nomination, defended his sibling on Twitter.

“How pathetic for @realdonaldtrump to criticize the president for 9/11,” Jeb Bush he wrote. “We were attacked & my brother kept us safe.”

Ari Fleischer, who was Bush’s White House press secretary during the 9/11 attacks, told The New York Daily News that Trump was “getting closer to truther territory if he thinks George Bush is the reason 9/11 happened.”

So-called “truthers” claim that the accepted narrative of Sept. 11, 2001, was faked to mislead the public about the true conspirators behind the attacks that killed nearly 3,000 people at the WTC, Pentagon and in Pennsylvania.

George W. Bush’s spokesman said the former president would not comment. “President Bush won't be commenting on this or anything Mr. Trump says,” spokesman Freddy Ford told the news.