US Defense Secretary Pete Hegseth has defended the military operation against Iran, calling it a "courageous and historic effort", and vowed to oppose attempts by Democrats to impeach him.

Axar.az reports that Hegseth made the remarks in a video message issued on Thursday.

"Regardless of how people feel about the war, which I believe is a courageous and historic effort that will ensure Iran never gets a nuclear weapon, we need to continue, as President Trump did in his first term, to rebuild our military," he said.

Hegseth also accused a defeated Democratic congressman and his party allies of filing what he described as baseless articles of impeachment against him, comparing the move to the two impeachment attempts against President Donald Trump.

"You see, their policies don't work. So, their obsession with political theater disguised as power drives them to try to destroy their opponents. It's all about the politics of personal destruction.

Didn't work against President Trump and it won't work with me. You can rest assured of that.

You see, they attack me, they attack us because we are effective. It's not going to work. We will not back down. We put America and the war fighter first. Always and without apology," Hegseth said.