US President Donald Trump has said that Saudi Arabia is "disintegrating", remarks made in an interview released on Friday that are likely to offend the kingdom as it endures missile and drone strikes from Yemen's Houthis.

Trump delivered his judgment on Saudi Arabia, one of Washington's closest allies, in an interview with Stephen A Smith. He boasted that he could destroy Iran within three days by striking civilian infrastructure, but said Saudi Arabia and other Gulf states had asked him not to because of their own vulnerabilities.

"If I want to take them out, I hit their [energy] in one day. Their energy is gone. In one day, their bridges are gone, and in one day, their manufacturing capability is gone. It would only take me three days, one day each," Trump said.

"Saudi Arabia has asked me to please just let it be the way it is now for a while because they're disintegrating," Trump said. "Qatar, if you look at that, Kuwait, UAE, Bahrain, all of them would much prefer the waiting period," he added.

This is not the first time Trump has appeared to relish boasting about the leverage he holds over Gulf states and, in particular, Crown Prince Mohammed bin Salman. Saudi Arabia has depended on the United States as its security guarantor since World War II. "He (MBS) didn't think this was going to happen.. he didn't think he'd be kissing my ass.. he thought it'd be just another American president that was a loser.. but now he has to be nice to me," Trump said in March, when the war on Iran was in full swing.

While Saudi Arabia avoided the worst of the US-Israeli war on Iran, which saw smaller Gulf states pummelled with missiles and drones in retaliation, it has since come under attack from the Houthis in Yemen. A ceasefire there between the Saudi-backed internationally recognised government and the Iran-aligned Houthis collapsed over the summer, and fighting is now raging.

The Houthis have struck Saudi airports, energy infrastructure and cities. The attacks have forced the kingdom to cancel key conferences intended to promote its non-oil economy and have interfered with the export of energy supplies.

Trump's assessment of the war's toll on Gulf states is shared by many analysts, but his own secretary of state, Marco Rubio, brushed off concerns this week that Gulf countries were suffering. Trump noted that the Gulf states have invested "trillions of dollars" in the US. In September, the US State Department approved the sale of up to 48 F-35 warplanes to Saudi Arabia, a historic deal that could total $24bn.

"They're tremendous investors in our country. They spend trillions of dollars in our country," Trump said of the Gulf. "The people that we're here to protect would rather have me do it the way I'm doing it now."

The Trump administration says it has no plans to resume a full-scale war on Iran, intending instead to strangle its economy by blockading the Strait of Hormuz. "The only oil that's not getting out consistently, through the Strait of Hormuz, is Iranian oil," Rubio said earlier this week. "The economic pressure on Iran is so devastating.. that the president's concluded.. there's no need for major combat operations."