Army Chief of Staff Gen. Ray Odierno said on Wednesday that Republican presidential candidate Donald Trump’s idea of using the U.S. military to seize oil reserves from the Islamic State terrorist group wasn’t going to work.

Trump told CNN’s Anderson Cooper earlier this month that if elected President he would bomb sites controlled by the terror group.

“I’d bomb the hell out of the oil fields,” he said. “I’d then get Exxon, I’d then get these great oil companies to go in — they would rebuild them so fast your head will spin … you ever see how fast they put up rigs? These guys are unbelievable.”

Odierno took questions from the media on Wednesday on the cusp of his retirement after 39 years of service. Among them, he was asked whether Trump’s comments had any “military utility,” according to the Washington Post.

“The problem we’ve had is we’ve had outcomes, but they’ve been only short-term outcomes because we haven’t properly looked at the political and economic side of it,” Odierno said, according to the newspaper. “It has got to be three that come together. And if you don’t do that, it’s not going to solve the problem, and that is what I continue to look at.”

But, if the Islamic State group posed a direct and immediate threat to the United States, Odierno said the country’s leaders would maybe consider putting troops on the ground.

“That is not where we are today,” he said, according to the Post.

“What we want to do is try to stop… a group that is potentially attempting to be a long-term influence in the Middle East, that is clearly promoting extremism and frankly suppressing the populations in the Middle East,” Odierno said, according to the publication. “In order to resolve that, you need countries of the Middle East and those surrounding the Middle East to be involved in the solution.”

The Post reported that when a reporter asked Odiderno whether he disagreed with Trump, he said, “I do, I do. Right now, I do.”