WASHINGTON — Defense Department officials told senators in a closed-door briefing Tuesday that they estimate the first six days of the war in Iran cost more than $11.3 billion, according to three sources familiar with the briefing.

Sen. Chris Coons, D-Del., told reporters Wednesday that he believes the amount is even higher, as the current figure does not include every aspect of the war.

“I expect that the current total operating number is significantly above that,” Coons said. “If all you’re looking at is the replacement cost for the munitions used, it’s already well beyond $10 billion.”

The Pentagon did not immediately respond to a request for comment on the briefing to the Republican-led Senate Appropriations subcommittee on defense. The briefing was first reported by The New York Times.

The cost estimate for less than a week’s worth of warfare comes as the Trump administration is determining how much it will request from Congress in a supplemental funding bill to cover the growing cost of the conflict. The appropriations subcommittee will be instrumental in crafting that legislation.

The war, now into its 11th day, has caused hundreds of casualties in the Middle East. Israeli and American strikes have killed more than 1,200 people in Iran, according to the Iranian Red Crescent Society. Thirteen people have died in Israel, and six have died in the United Arab Emirates, while 570 people in Lebanon have died, according to the Lebanese prime minister’s office.

Seven U.S. service members have died in the war, and 140 have been wounded.

It’s unclear how much longer the war will last. President Donald Trump gave conflicting remarks Tuesday, saying the war would end “very soon,” while he said at the same event that Defense Secretary Pete Hegseth’s claims that it was only “the beginning” could also be correct.

“I think you could say both,” Trump said.

Tensions are heightening as at least three ships have been attacked on the Strait of Hormuz, which Trump said would cause the U.S. to escalate attacks against Iran. U.S. Central Command said Wednesday that it had “eliminated” 16 Iranian minelayers and multiple naval vessels near the strait.