The US State Department has issued a worldwide travel caution warning American citizens that flights could be cancelled or disrupted as the conflict with Iran escalates. The advisory reflects growing concern within the US government that the situation could deteriorate further, prompting officials to urge Americans travelling abroad to remain vigilant and prepared for sudden changes to air travel.

The warning follows an attack on an American airbase that left two US service members dead and another missing, after which Washington vowed to "punish" Iran with a fresh barrage of strikes. The escalating tit-for-tat raises the prospect of wider disruption to international air travel as tensions between the US and Iran continue to intensify.