Saudi Arabia says its initial investigations indicate that Iranian weapons were used in attacks on key oil installations and it “will invite U.N. and international experts to view the situation on the ground and to participate in the investigations.”

A statement from the Saudi Ministry of Foreign Affairs on Monday says, “The kingdom will take the appropriate measures based on the results of the investigation, to ensure its security and stability.”

The ministry says Saudi Arabia “affirms that it has the capability and resolve to defend its land and people, and to forcefully respond to these aggressions.”

It called Saturday’s attack that resulted in the suspension of approximately 50% of Saudi Aramco’s production “an unprecedented act of aggression and sabotage” and “egregious crime which threatens international peace and security.”