President Trump said Wednesday former President George W. Bush is responsible for the biggest mistake in American history.

“The worst single mistake ever made in the history of our country: going into the Middle East, by President Bush,” Trump said during an interview with the Hill. “Obama may have gotten [U.S. military personnel] out wrong, but going in is, to me, the biggest single mistake made in the history of our country.”

Trump, who failed to win Bush's vote in the 2016 presidential election, blamed the spiraling cost of the war efforts in the region.

“Because we spent $7 trillion in the Middle East," the president said. "Now if you wanna fix a window some place they say, 'Oh gee, let’s not do it.' Seven trillion, and millions of lives — you know, ‘cause I like to count both sides. Millions of lives.”

“To me, it's the worst single mistake made in the history of our country. Civil War you can understand. Civil War, Civil War. That’s different," the president continued. "For us to have gone into the Middle East, and that was just, that was a bad day for this country, I will tell you.”

This is not the first time Trump has spoken about the cost of conflicts in the Middle East. He mentioned the $7 trillion figure in a tweet in February.

"This will be a big week for Infrastructure," he wrote on Twitter. "After so stupidly spending $7 trillion in the Middle East, it is now time to start investing in OUR Country!"

According to Politifact, the U.S. has spent about $2 trillion thus far on military-related activity in Iraq, Afghanistan, Pakistan, and Syria. Trump's claim is based on projected expenditure in the region by 2053 calculated by Boston University political scientist Neta Crawford, including future costs associated with treating wounded veterans and debt accrued.