US embassies in capitals across the Middle East on Saturday warned their citizens to beware of "unforeseen escalation" in the regional conflict and urged them to be ready to leave. Advertisement AdvertisementAdvertisement AdvertisementWith no end in sight, the war has for months upended the lives of people across the Middle East and rattled global energy markets. "Americans currently in the Middle East should exercise caution and heightened vigilance and should be prepared for flight cancellations, periodic airspace closures, and potential travel disruptions," it said. - 'Defensive shield' -Iran's military on Saturday accused Washington of "escalating tensions" in the region. The Middle East war broke out when the United States and Israel launched strikes on Iran, which has retaliated with missile and drone strikes across the region.