By Timour Azhari and Enas Alashray

RIYADH, Oct 10 (Reuters) - Several people were wounded in an attack on King Khalid International Airport in Saudi Arabia's capital Riyadh on Saturday that forced a suspension of operations, the country's civil aviationauthority said.

There was no immediate claim of responsibility for the attack, but it comes amid an escalation of missile strikes by Yemen's Iran-aligned Houthis against Saudi Arabia.

The airport had already been struck in two earlier attacks this week that left four people dead and exposed vulnerabilities in the kingdom's ability to defend itself as it wages war on the Houthis.Saudi Arabia's early warning system did not issue an alert ahead of Saturday's incident.

The Saudi government's media office did not immediately respond to questions from Reuters.

One eyewitness at the airport on Saturday reported seeing an explosion and then multiple people lying injured on the ground inside. More than a dozen ambulances were seen rushing towards the facility.

An injuredtraveller told Reuters they saw something fly across the sky outside the airport before part of the ceiling near a departure gate collapsed.

US TO "LOOK AT" JOINING SAUDI FIGHT AGAINST HOUTHIS: TRUMP

Following the attack, US President Donald Trump, speaking to reporters outside the White House, was asked whether the United States planned to join Saudi strikes on the Houthis.

"We may. We're going to look at it. We just found out about the recent attack, so we'll make a decision. We move very quickly," he said.

The US embassy in Riyadh said it was "aware of attacks" and "strongly recommends all US citizens avoid this airport and surrounding areas."

The UK and Irish embassies in Saudi Arabia said in statements on X that they were also aware of a "serious incident" at the airport. The Canadian embassy said that "ongoing military activity" had impacted operations at the airport.

RIYADH DUE TO HOLD MAJOR SUMMITS

Flight-tracking site flightradar24 showed all flights to Riyadh had either been diverted or cancelled, with only a helicopter hovering over the airport at one point.

Kuwait Airways said it had cancelled flights to and from the Saudi capital due to what it described as the closure of Riyadh airport because of the "security situation" there.

Etihad Airways and Qatar Airways earlier cancelled multiple flights between their respective hubs and Riyadh, with some cancellations extending into Monday.

Houthi attacks on Thursday and earlier in the week had already prompted a number of carriers to suspend or cancel services to the Saudi capital, shortly before Riyadh is due to host major energy and investment conferences.

Organisers of those conferences said on Saturday they would go ahead as planned, and they sought to reassure attendees of their security.

The Houthis have said airliners should avoid Saudi airspace, declaring it a zone of military operations after the Saudi-backed Yemeni government launched an offensive against the group earlier this month.

(Reporting by Timour Azhari in Riyadh; Additional reporting by Steve Holland in Washington DC; Writing by Enas Alashray and Maya Gebeily;Editing by Gareth Jones and Joe Bavier)