The U.S. State Department has issued a global security alert, urging American citizens to exercise increased caution following a U.S. military strike in Tehran amid escalating tensions between Iran and Israel. The conflict has disrupted Middle East travel and led to temporary airspace closures. The Department of Homeland Security also warned of a heightened threat environment, citing risks of cyberattacks and lone-wolf assaults. Iran warned it would target any country aiding U.S. attacks, intensifying fears of broader regional instability.