Mark Esper
Mark EsperReuters

US Defense Secretary Mike Esper said on Monday that the US military is preparing a response to the attack on major Saudi Arabia oil facilities, AFP reported.

After briefing President Donald Trump in the White House, Esper singled out Iran as undermining international order, without directly pinning blame on Tehran for the attack.

"The United States military, with our interagency team, is working with our partners to address this unprecedented attack and defend the international rules-based order that is being undermined by Iran," he said in a tweet.

Earlier on Monday, Trump said that it’s “looking like” Iran was responsible for the weekend attacks on Saudi Arabia’s oil supply.

His comments came a day after he issued a veiled warning to Iran following the attack on Saudi Arabia’s oil facilities.

While Trump did not mention Iran, he wrote on Twitter, “Saudi Arabia oil supply was attacked. There is reason to believe that we know the culprit, are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of this attack, and under what terms we would proceed!”

Saudi Arabia said that the drone strikes on its key oil facilities disrupted about half of the kingdom's oil capacity, or 5% of the daily global oil supply.

Yemen's Houthi rebels took responsibility for the attacks, saying 10 drones targeted state-owned Saudi Aramco oil facilities in Abqaiq and Khurais.

While Iran sponsors the Houthi rebels, it has long denied that it is doing so and rejected accusations that it is behind Saturday’s attack.