U.S. President Donald Trump said U.S. forces have hit 28 Iranian minelaying ships as of Wednesday.

“They started talking about mines, so we hit 28 mine ships as of this moment,” CBS News quoted Trump as saying while touring a pharmaceutical company in Cincinnati.

U.S. officials had told CBS News that Iran may have been preparing to use naval mines in the key Strait of Hormuz off the Iranian coast.

A reporter asked President Trump on the White House South Lawn Wednesday what more needs to happen militarily for the operation in Iran to end.  

“More of the same,” the president responded. “And we’ll see how that all comes out. Right now, they’ve lost their navy, they’ve lost their air force, they have no anti-aircraft apparatus at all. They have no radar. Their leaders are gone. And we could do a lot worse.” 

When he was asked about the latest reporting suggesting the U.S. may be at fault for the deadly strike at a school in Iran, the president said, “I don’t know about it.”

Iran said that 170 schoolgirls were killed in a school in Minab in a U.S. Tomahawk strike on the first day of the military operations. The U.S. said it would investigate. Initially, the U.S. president suggested to reporters that Iran might be behind it. But Reuters, CBS News and New York Times reported that a preliminary military investigation into the bombing of the elementary school found the U.S. was likely responsible.