The U.S. Mission in Saudi Arabia has directed U.S. government employees working in the kingdom to obtain “special authorisation” before embarking on official or personal trips to Taif and Yanbu amid heightened security concerns.

“Due to the ongoing security situation in Saudi Arabia, U.S. government employees who work in Saudi Arabia now require special authorization for all official and personal travel to the cities of Taif and Yanbu,” the statement said Sunday. “The U.S. Mission strongly encourages all U.S. citizens to remain vigilant.”

The mission also advised Americans in Saudi Arabia to avoid glass doors and windows in the event of an aerial attack.

“If an aerial attack occurs, stay away from glass doors, windows, and any fallen debris, and monitor your phone and news outlets for official guidance,” the advisory said.

The latest restrictions came after the U.S. Department of State urged Americans to reconsider travel to Saudi Arabia over the risk of Iranian drone and missile attacks targeting U.S. interests.

Earlier this month, Saudi Arabia also temporarily shut its critical East-West oil pipeline after it was hit by drones launched from Iraq, according to the kingdom.

The attacks pushed global oil prices higher, with Brent crude rising above $100 a barrel and U.S. diesel prices surpassing $6 per gallon.

In Nigeria, petrol prices have also risen, with pump prices in Abuja reaching around N1,600 per litre while black market prices climbed as high as N1,750 per litre.