United States on Saturday issued a fresh travel advisory for Americans travelling to the Middle East and warned of a possible rapid escalation amid Houthi missile and drone attacks towards Saudi Arabia.The US state department, in its advisory, urged Americans in the Middle East to exercise heightened vigilance and remain prepared for possible flight cancellations, airspace closures and other travel disruptions. The department also warned that Iran and groups supportive of Tehran could target US interests, businesses and institutions overseas.“Due to tensions in the Middle East, the security environment remains complex with the potential for unforeseen escalation. Americans currently in the Middle East should exercise heightened vigilance and be aware of potential flight cancellations, airspace closures, and travel disruptions,” the advisory said.“Iranian-supported Houthis have engaged in hostilities against Saudi Arabia, including civilian airports. This military conflict has the potential to escalate rapidly. Americans outside the Middle East should seriously reconsider travel to and through the region. Those who do travel to or from the region should monitor information about airport and airline operations,” it added .For Saudi Arabia, the US state department has maintained a Level 3 – reconsider travel advisory. The department cites the risk of Iranian drone and missile attacks targeting American interests, armed conflict, terrorism, exit bans and local laws concerning social media activity.The state department said Iranian missiles and drones have previously targeted cities, infrastructure, airports, military bases, diplomatic facilities and energy installations in Saudi Arabia. It also warned that falling debris from intercepted projectiles could pose a risk.US government employees in Saudi Arabia face additional restrictions, including a prohibition on travel within 20 miles of the Yemen border. Special authorisation is required for travel to Jizan, Asir, Najran and Qatif.The department also warned that commercial flights from Saudi Arabia remain operational but have faced significant disruptions amid the conflict.Meanwhile, Yemen remains under a Level 4 – do not travel advisory, with the state department citing terrorism, armed conflict, kidnapping, unrest and other security risks.This comes after Yemen’s Houthis launched ballistic missiles towards Saudi Arabia’s Riyadh and targeted civil infrastructure in Bisha, Taif, Farasan and Yanbu. Saudi Arabia, however, said that the missiles were intercepted.Saudi Arabia issued emergency alerts across the kingdom overnight on Friday, warning of a “hostile aerial threat”. Al Jazeera reported that at least one explosion was heard in Riyadh on Saturday, while residents near the airport reported seeing a large plume of black smoke. Saudi authorities reported no casualties or damage.The US state department has separately maintained a Level 3 – reconsider travel advisory for Israel.The department also warned that US diplomatic facilities and American interests could face threats from Iran and groups supportive of Tehran, including at locations outside the Middle East.