The U.S. has asked Americans planning to travel to the Middle East, particularly Saudi Arabia, to reconsider as Iran extends hostilities to U.S. allies.

“Americans outside the Middle East should seriously reconsider travel to and through the region,” a Department of State travel advisory said.

Given the distance between the U.S. and Iran, the Islamic State was targeting U.S. military bases in neighbouring countries allied with the Donald Trump administration.

“Americans currently in the Middle East should exercise heightened vigilance and be aware of potential flight cancellations, airspace closures, and travel disruptions,” the advisory added.

The Department of State said, “Iranian-supported Houthis have engaged in hostilities against Saudi Arabia, including civilian airports. This military conflict has the potential to escalate rapidly.”

A Saudi Arabian pipeline was hit by drones earlier this month, roiling oil prices across the world. Diesel soared to $6 in the U.S., and petrol increased to N1600 per litre in Nigeria.

The U.S. and Israeli governments decapitated Iran on February 28, killing its supreme leader, Ayatollah Khamenei. Iran retaliated by shutting down the Strait of Hormuz, a critical route for one-fifth of global oil supply.

The U.S. Navy mounted a blockade at the strait to prevent Iran from shipping its own oil while stopping the rest of the world.

Negotiations between both nations are at an impasse, as neither Washington nor Tehran has agreed to capitulate.