“No, the strait’s got to be open to everybody; it’s international waters,” the president told reporters during a Cabinet meeting on Wednesday. “We’ll watch over it, but nobody’s going to control it. That’s part of the negotiation that we have.”

“They would like to control it; nobody’s going to control it. It’s international waters. And Oman will behave just like everybody else, or we’ll have to blow ’em up. They understand that. They’ll be fine.”

It was unclear whether the president was serious in his intent to threaten Oman or if it was a joke, though the State Department shared a clip of this comment on social media, reiterating the message.

The two countries formalized their relationship with the 1833 signing of the “Treaty of Amity and Commerce,” and it was the first American bilateral accord with an Arab Gulf State. Oman and the US expanded their relationship with the signing of the “Treaty of Amity, Economic Relations, and Consular Rights” in 1958, and the U.S. opened its embassy in Muscat in 1972, while they opened their embassy in Washington, D.C., the following year.

The U.S. and Iran are negotiating an end to the war, but the two sides remain deeply divided on several issues. At times, Trump says the deal has been “largely negotiated, subject to finalization,” and other times he has said the opposite, like that critics of the proposed deal are wrong because “things that haven’t even been negotiated yet.”

While the U.S. has worked alongside Gulf countries during the war — where Iran fired thousands of drones and hundreds of missiles at targets, military and civilian, across the Gulf countries — and in the interim ceasefire, there have been little cracks emerging between them.

The president announced Project Freedom, an effort in which the U.S. Navy would guide ships through the strait to avoid Iranian attacks, but Gulf countries urged him to quickly end the endeavor due to concerns that they would bear the brunt of Iran’s retaliation. In the short time the mission was operational, Iran fired on ships and at the United Arab Emirates, emphasizing that fear.

Separately, Trump announced on May 18 that he would be holding off on a planned attack on Iran, citing requests from Gulf leaders.

Earlier this week, the president urged Gulf countries to join the Abraham Accords, Trump’s signature foreign policy achievement during his first term, in which Israel normalized relations with Sudan, the United Arab Emirates, Bahrain, Morocco, and, most recently, Kazakhstan.

TRUMP SAYS GULF STATES SHOULD RECOGNIZE ISRAEL AS PART OF DEAL TO END IRAN WAR

He thinks Saudi Arabia, the United Arab Emirates, Qatar, Pakistan, Turkey, Egypt, and Jordan should “at a minimum, simultaneously, sign onto the Abraham Accords.”

During Wednesday’s Cabinet meeting, Trump said, “I’m not sure we should make the deal if they don’t … join the Abraham Accords.”