Oil futures surged midday Thursday as escalating attacks on Gulf shipping and renewed Houthi strikes on Saudi Arabia heightened concerns over disruptions to global energy supplies.

Both crude benchmarks crossed $100/bbl on Thursday, West Texas Intermediate for the first time since May. As of 11:25 a.m. ET, November ICE Brent crude was trading $4.54 higher at $105.75/bbl, with December up $3.93 at $101.03/bbl. The October WTI contract rose $4.41 to $100.36/bbl, with November WTI up $3.56 at $96.43/bbl.

Refined product futures were also advancing, with October ULSD up 21.43cts at $5.0153/gal and November ULSD up 19.32cts at $4.8179/gal. October RBOB rose 14.44cts to $3.355/gal, while November RBOB climbed 12.58cts to $3.1739/gal.

U.K. Maritime Trade Operations said Wednesday it received reports of several merchant vessels coming under fire in the northern Persian Gulf and Gulf of Oman, while Iran's Islamic Revolutionary Guard Corps warned of further restrictions on shipping around the Strait of Hormuz.

Houthi militants also seized the Yemeni port city of Mokha on Thursday, expanding their control near the Bab al-Mandeb chokepoint. The development adds pressure to an alternative route for Saudi crude exports as disruptions through the Strait of Hormuz have pushed the kingdom to move more oil across the country for shipment from the Red Sea.

The Energy Information Administration estimated Middle East crude-production shut-ins averaged 6.7 million b/d in August and expects them to average 5.7 million b/d in the fourth quarter.