(CNN) –  In a TV interview Friday, GOP frontrunner Donald Trump partly laid the blame for the 9/11 terrorist attacks at the feet of former President George W. Bush.

“When you talk about George Bush, I mean, say what you want, the World Trade Center came down during his time,” Trump said in a Friday interview with Bloomberg TV.

The Republican presidential candidate seemed to imply Bush shared responsibility for the acts of terrorism that took down the Twin Towers.

“He was president, OK? Don’t blame him, or don’t blame him, but he was president. The World Trade Center came down during his reign,” Trump said in the interview.

Jeb Bush, the former president’s brother and Trump’s fellow COP candidate, responded via Twitter.

“How pathetic for @RealDonaldTrump  to criticize the president for 9/11,” Jeb Bush tweeted. “We were attacked and my brother kept us safe.”

For his part, the usually talkative Trump has so far refused to answer questions on the subject. But the candidate has responded on social media, engaging in a Twitter war with his Republican rival.

“No, @JebBush, you’re pathetic for saying nothing happened during your brother’s term when the World Trade Center was attacked and came down,” Trump Tweeted,

Trump’s comments are spurring other GOP candidates to weigh in.

Ben Carson said he didn’t hear Trump’s remarks, but when asked if he thought Bush shared responsibility for the attacks, he responded, “I think it’s ridiculous to suggest that he’s responsible for that.”

In the Bloomberg interview, Trump also criticized the Obama administration’s response to the Sandy Hook tragedy. He said, “What we need is a leader; we don’t have a leader.”

Copyright 2015 CNN. All rights reserved.