To commemorate the 20th anniversary of the 9/11 attack, former U.S. President George W. Bush gave a speech about how this one moment permanently changed not only the United States but also the world.

But while not directly criticizing anyone in his speech, it appears that one person took it as a personal attack and didn't hesitate to lash back: Former U.S President Donald Trump.

"So interesting to watch former president Bush, who's responsible for getting us into the quicksand of the Middle East (and then not winning!)," Trump said.

He added, in an emailed statement, that Bush "lectures us that terrorists on the 'right' are a bigger problem than those from foreign countries that hate America."

Trump remains banned from the Twitter platform until now, which was his preferred platform to air his opinions.

Sharp response

In his speech, Bush said that one of the greatest dangers that the United States is facing right now isn't just its foreign enemies but also the growing violence inside the country.

He also said that even with the differences between extremists in the country and abroad, their lack of respect in life and national symbols makes them "children of the same foul spirit."

Bush highlighted that the government should continue its efforts to confront the country's enemies to finally make the United States a safe place for its citizens.

Trump quickly hit back and said that Bush shouldn't "lecture" anybody about 9/11 because the big terrorist attack happened under his watch. He even called Bush's Presidency "failed and uninspiring."

'Fake Media'

The former U.S. President, who is known for his brash way of speaking, and always at odds with the media, said that the current turn of events is truly disappointing.

He said that the media, or in his own words, the "Fake Media," are only interested in discussing terrorism and protecting Bush's image. He called Bush an "illegitimate president."

According to Trump, the U.S. has lost "trillions" of dollars in the two decades it has spent in Afghanistan.

He said that just nine months ago (referring to his Presidency), the U.S. was viewed as a strong nation but has now become the "laughingstock of the world."