President Donald Trump returned to the White House on Saturday evening, a day earlier than planned, after a Camp David meeting that CNN reported was held to review strike options against Yemen’s Houthis. The White House gave no explanation for the schedule change. The deliberations followed Houthi attacks on Saudi Arabia.

The State Department issued a regional security alert urging Americans to reconsider travel to or through the Middle East and warning those already there of possible flight cancellations, airspace closures and travel disruptions. It cited Houthi hostilities against Saudi Arabia, including civilian airports, and warned that the conflict could escalate rapidly. The department also warned that Iran and groups supporting it could target US interests worldwide, including businesses and other institutions.

The Houthis claimed missile and drone attacks on “sensitive sites” in Riyadh and Aramco facilities in Yanbu. The Saudi-led coalition said it intercepted and destroyed a ballistic missile headed toward Riyadh and thwarted attacks on other Saudi cities. An Aramco fuel tank near Riyadh’s King Khalid International Airport caught fire, and flights were canceled or delayed. Houthi military spokesman Yahya Saree did not specifically identify the airport as a target.