Brent crude futures opened 1% higher Sunday evening as a Houthi attack on Saudi Arabia’s capital fueled concerns about supply disruptions. US crude was up 1%, trading above $100 a barrel early Monday, after earlier losses.

Prices swung as investors assessed a potential recovery in Saudi oil exports. US crude futures earlier fell more than $1 to $99.22, and both benchmarks subsequently posted declines of $2. Efforts to restore Saudi export capacity and increased tanker movements through the Strait of Hormuz eased some supply concerns.

Yemen’s Houthis said Saturday they attacked “sensitive sites” in Riyadh and Aramco facilities in Yanbu with missiles and drones. An Aramco fuel tank near Riyadh’s King Khalid International Airport caught fire, and flights were canceled or delayed. The Saudi-led coalition said it intercepted a ballistic missile aimed at Riyadh and thwarted attacks on other cities. Saudi authorities reported no casualties.