Saudi Arabia said some of the world’s most protected oil infrastructure came under missile and drone attack in an escalation of regional hostilities that pushed up crude prices. The attacks on Sunday were intercepted, Saudi Arabia said, and oil output appeared to be unaffected. But the latest in a spate of assaults claimed by Iran-backed Houthi rebels briefly pushed oil prices above $70 a barrel for the first time since January 2020 and will likely complicate efforts by US President Joe Biden to engage in nuclear diplomacy with Iran. The attacks are the most serious against Saudi oil installations since a key processing facility and two fields came under fire in September 2019, cutting production for about a month and exposing the vulnerability of the kingdom’s petroleum industry. Yemen’s Houthi fighters claimed responsibility for that attack although Riyadh and Washington pointed the finger at arch-rival Iran. The US held back from military confrontation and said at the time it would boost air and missile defenses in the kingdom. On Monday, the US said its commitment to defend Saudi Arabia is “unwavering.” In a Twitter post, the U. S. mission in Riyadh condemned the attacks, which it said demonstrated a “lack of respect for human life” and a “lack of interest in the pursuit of peace.” An oil storage tank farm at the Ras Tanura export terminal on the Persian Gulf coast was attacked by a drone from the sea, according to the Energy Ministry. Shrapnel from a missile also landed close to a residential compound for employees of national oil company Saudi Aramco in Dhahran, where windows shook and witnesses said they took shelter.