Saudi Arabia is reportedly running short of interceptor missiles used to defend against continued attacks by Yemen’s Iran-backed Houthi rebels, according to a report by The Wall Street Journal citing Saudi officials.

The newspaper, citing individuals familiar with Riyadh’s thinking, reports that the kingdom is “struggling to cover the vast country with air defense.” Saudi authorities are reportedly repositioning missile defense batteries to prioritize protection for critical energy facilities and royal palaces.

Crown Prince Mohammed bin Salman is also taking precautions amid the threat, with the WSJ reporting that he is moving cautiously between “heavily guarded palaces equipped with bunkers” while accompanied by a select group of security personnel.