Jeb Bush fired back Friday after Republican presidential candidate Donald Trump knocked former President George W. Bush over the Sept. 11 terrorist attacks that brought down the World Trade Center.

Trump’s comments came after Bloomberg’s Stephanie Ruhle asked him if he would be capable of comforting the nation in the event of a mass catastrophe like the 9/11 attacks or the 2012 shooting in Newtown, Conn.

“I think I have a bigger heart than all of them,” Trump told Ruhle in response. “I think I’m much more competent than all of them. I mean, say what you want, the World Trade Center came down during his time.”

Ruhle pushed back, saying, “Hold on, you can’t blame George Bush for that.”

“He was president, okay? Blame him or don’t blame him, but he was president,” Trump said. “The World Trade Center came down during his reign.”

Jeb Bush struck back over social media, calling Trump’s comments “pathetic.”

His tweet: “How pathetic for @realdonaldtrump to criticize the president for 9/11. We were attacked & my brother kept us safe.”

Bush and Trump have tangled before over the former president’s record.

“Your brother and your brother’s administration gave us Barack Obama, because it was such a disaster those last three months that Abraham Lincoln couldn’t have been elected,” Trump told the former Florida governor at the CNN debate in September.

“You know what? as it relates to my brother, there’s one thing I know for sure. He kept us safe,” Bush replied.

Later, he tweeted a photo of his brother standing at Ground Zero.

“When it comes to my brother, there’s one thing I know for sure. He kept us safe.”

The business mogul has been critical of the former president in the past, publicly questioning his intelligence and his leadership on the war in Iraq. “He just didn’t seem smart. Does that make sense to you? He didn’t seem smart,” Trump told The Post in August. “I’d watch him in interviews and I’d look at people and ask, ‘Do you think he understands the question?’ I mean, he didn’t seem like he had it.”

Trump was scheduled to appear at a campaign event in Massachusetts Friday evening.