The head of US Central Command said it would take a "generation" for the Iranian navy to be rebuilt to its former strength, and said Jordan had been indispensable during the conflict.
Admiral Brad Cooper told the Senate armed services committee that the US has destroyed more than 90 per cent of Iran’s inventory of about 8,000 naval mines.
"The defence industrial base for their drones and their missiles and their navy were degraded by 90 per cent. They have about 10 per cent left for the navy," he said.
"My professional perspective on this also is that Iran would not return to the same level of navy that it had for a generation."
Admiral Cooper acknowledged that Iran still had the resources to launch attacks in the surrounding region, but not as wide-scale as before.
He said that Iran's offensive abilities have been degraded to the point where they no longer pose a major threat to the US or its regional partners.
But Senator Elissa Slotkin, a Democrat, asked why the US has not reopened the Strait of Hormuz if Iran was no longer a military threat.
"If the United States military is not physically opening the straits right now, it's because the Iranians do have the real capability to effect strikes in or drone strikes into the Gulf countries, affecting their oil infrastructure and sending the price of oil worldwide even higher," Ms Slotkin said. "It may be diminished but it's a real capability, unless I'm missing something."
The Centcom chief also praised regional allies for their support, particularly Jordan.
"Everything that we've accomplished would have been impossible without the kingdom of Jordan," he said, adding that the US was also operating very closely with Israel. "We're always eager to expand partnerships."
Jordan usually hosts about 4,000 US soldiers as well as US military sites including the main Muwaffaq Salti Air Base. Over the course of the conflict, Iran hit Jordan with about 280 missiles and drones, according to the military.
Amman also receives significant US military aid. Since 2015, the US has provided Jordan with $2.1 billion in foreign military funding, making it the third largest global recipient of military aid.
Admiral Cooper thanked the UAE, Bahrain, Kuwait, Qatar and Saudi Arabia for their support during the conflict.
"Over the course of Epic Fury, they defended themselves and they defended Americans," he said.
Senator Joni Ernst also praised the Gulf countries, particularly the UAE, which she said "has taken a significant amount of incoming fire".
"They haven't all been passive bystanders," she said. "They have contributed to every line of effort, and we appreciate them contributing to our successes."
Admiral Cooper added that an "air defence umbrella" the US and allies had been working towards for most of a decade was made possible through close relationships with Gulf partners.
Without elaborating, however, he indicated that some allies had not pulled their weight.
"There's a couple that I think I could address in a classified setting that were less than stellar," Admiral Cooper said.
