President Trump on Thursday said his administration hopes to boost spending on missile defense by "many of billions of dollars" to deal with the threat of a nuclear-armed North Korea.

"We're going to be increasing our budget by many billions of dollars because of North Korea and other reasons having to do with the anti-missile [defense system]," Trump told reporters after a security briefing with his team.

"As you know, we reduced it by five percent but I've decided I don't want that," he continued. "We're going to be increasing the anti-missile by a substantial number of billions."

The president's comments come weeks after Defense Secretary Jim Mattis told a House panel that Pentagon officials would need to complete a study on U.S. missile defense before the administration could request additional funding from Congress.

"Right now, I think we can first do the study to make sure what is the requirement," Mattis told Rep. Doug Lamborn, R-Colo., on June 12. "I want to get this right before we come to you and spend a lot of money. You're going to count on us that we did our homework, and we've not yet done it."

The administration has pressed the need for a "state-of-the-art missile defense system" to shield the U.S. from missile-based attacks from actors like North Korea and Iran.

A White House blueprint released in March set the target budget for the Missile Defense Agency at $7.9 billion, a relatively modest increase of $379 million from the previous year.

The agency has said additional funds would be used to expand Ground-based Midcourse Defense (GMD) capabilities and relocate several ground-based missile interceptors to Alaska to improve protection against North Korea. The funds would also be used to modernize ground system infrastructure, according to a report released in May.