The US State Department has released a global security alert advising American citizens overseas to remain on high alert, citing concerns that Iran-backed or pro-Iran groups could target Americans as tensions between Washington and Tehran continue to intensify.The U.S. Embassy in Amman advised Americans to avoid Aqaba's airport and seaport. (Getty Images via AFP)“Due to heightened tensions in the Middle East, the security environment remains complex with the potential for unforeseen escalation,” the State Department said in an alert posted Saturday.Global alert after Jordan attackThe advisory comes two days after an Iranian attack in Jordan killed two US service members and left four others requiring medical evacuation.Although the notice specifically references the worsening situation in the Middle East, officials stressed that Americans across the globe should remain cautious.“Americans abroad should follow the guidance in security alerts issued by the nearest US embassy or consulate,” the department said.Conflict expands across regionEarly Monday, the United States carried out another wave of airstrikes, targeting locations near a northwestern Iranian city believed to contain underground missile facilities. The operation came shortly after US officials confirmed the death of another American service member.Iran retaliated by launching strikes targeting Bahrain, Kuwait, Saudi Arabia and Jordan. Bahrain hosts the US Navy's Fifth Fleet, making it a key American military hub in the region.Also read: Fresh US strikes on Iran, bases hit in Bahrain, Trump warns Tehran 'will pay': Top 6 updates on Iran war“Now that the American enemy is seeking to escalate the conflict thereby incurring even heavier costs and further humiliation, it should know that the noble nation of Iran and the Resistance Front have unforgettable lessons in store for it,” Iran’s Supreme Leader Mojtaba Khamenei said in a statement reported by Iranian state media.Airports face security threatsRegional transportation hubs have also faced growing security concerns. Jordanian authorities recently evacuated Aqaba's international airport following intelligence about a specific threat, while Kuwait International Airport has repeatedly been targeted by Iranian missiles and drones.Following the evacuation in Jordan, the US Embassy in Amman issued its own security advisory, urging American citizens to stay away from Aqaba's airport and seaport.The embassy also instructed travelers to “keep a low profile.”Travel advisory measures explainedThe State Department further encouraged travelers to check the latest Travel Advisories and embassy-issued security alerts on travel.state.gov before departing for international destinations.Also read: US identifies its 2 soldiers killed in attack as Iran says it's ‘full-scale war’ now“Flight cancellations and periodic airspace closures may cause travel disruptions,” the State Department warned on Saturday.In addition, US officials urged Americans traveling abroad to register through the Smart Traveler Enrollment Program (STEP), allowing the nearest US Embassy or Consulate to provide emergency notifications and assistance if needed.