US President Donald Trump cut short a weekend at Camp David to return unexpectedly to the White House on Saturday, as tensions rose in the Middle East.

There was no explanation from the administration why Trump was no longer returning on Sunday from Camp David, a secluded presidential complex in rural Maryland, as had been previously announced.

However, it is not uncommon for White House travel to change on weekends, including for weather reasons. Forecasts showed rain and thunderstorms in the hilly Camp David area on Sunday.

The change in plan came as the Saudi-led coalition fighting Yemen’s Houthis said on Saturday that the Iran-backed group fired a ballistic missile at Riyadh at dawn, after a fire broke out near the Saudi capital’s international airport.

The State Department and a string of US embassies issued security alerts to Americans.

The alerts cited “the potential for unforeseen escalation” and noted that “Iranian-supported Houthis have engaged in hostilities against Saudi Arabia, including civilian airports.”

“This military conflict has the potential to escalate rapidly,” the State Department warning said. “Americans outside the Middle East should seriously reconsider travel to and through the region.”

AFP