Defense Secretary Pete Hegseth told reporters Tuesday morning from the Pentagon that "today will be yet again our most intense day of strikes inside Iran."
Hegseth's statement came shortly after he said that "the last 24 hours have seen Iran fire the lowest amount of missiles they have fired yet."
WATCH: Iran's Araghchi calls U.S. strikes a 'failure' and vows to fight 'as long as it takes'
Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said at the same news conference that the U.S. military is moving into the 11th day of its operation against Iran.
Iran is firing off fewer ballistic missiles, drones since U.S. campaign began
Caine said the number of ballistic missiles fired off by Iran continues to go down since the first day of the U.S. military's campaign against Iran.
Speaking at the Pentagon news briefing, Caine said missile attacks have fallen 90% and one-way attack drones have decreased 83% since the war began.
Hegseth said the numbers show U.S. strikes are making progress by wearing down Iran's defenses and its ability to strike its neighbors and U.S. forces.
"That is strong evidence of degradation," Hegseth said of the numbers.
Top U.S. general says no request for tanker escorts through the Strait of Hormuz yet
Caine said the military is considering options to ensure the Strait of Hormuz is open for tanker traffic but has not yet been asked to escort tankers through the narrow passage.
He also said military leaders are looking at "a range of options" and would present them to Trump if asked.
WATCH: Oil expert warns of 'nightmare scenario' Iran war could spark
Hegseth noted Trump's threat on Monday to increase strikes on Iran by 20 times if it stops the flow of oil through the Strait. He also said Iran's decision to target its neighbors was a desperate move that would only drive other Middle East nations toward the U.S.
"I can't say that we anticipated necessarily that's exactly how they would react," Hegseth said.
Hegseth says U.S. is taking the investigation on a school strike 'very seriously'
Responding to a question shouted by a reporter at a news conference about accountability for the strike, Hegseth said that "we take things very, very seriously and investigate them thoroughly."
"No nation takes more precautions to ensure there's never targeting of civilians," he said, adding that "open source information" shouldn't be used to determine what happened.
WATCH: Trump sidesteps responsibility for deadly strike on Iranian girls' school
Satellite images, expert analysis, a U.S. official and public information suggest the explosion that killed at least 165 people, mostly children, was likely caused by U.S. airstrikes that also hit an adjacent compound associated with Iran's Revolutionary Guard.
Trump erroneously claimed Monday that Iran has access to the American Tomahawk cruise missile, the weapon likely used to strike the school.