The National Resistance Forces in Yemen, which are backed by the Saudi Arabian government, have launched a counteroffensive against the Houthi rebels.
U.S. oil prices reached their highest levels since the beginning of June on Tuesday after Saudi Arabia announced that a wave of attacks by Houthi rebels hit oil facilities.
The West Texas Intermediate contract for October delivery (CL00) (CLV26) advanced 3%, to $94.36 a barrel, marking the U.S. benchmark's highest price in over three months.
Brent crude's November contract (BRN00) (BRNX26) meanwhile climbed 2% to almost $99 a barrel, the international benchmark's highest price since July 23.
The moves come amid worsening tensions between Yemen's Iran-backed Houthi rebels and Saudi Arabia.
Major-General Turki al-Maliki, a spokesman for the Saudi-led coalition in Yemen, said in a statement that the Houthi attacks in Jazan, Najran, Abha and Khamis Mushait had hit "civilian and economic facilities." He said 73 people were injured in the attacks.
The country's energy ministry added that energy facilities were targeted, with fires starting at several sites - leading to some operations being halted.
The Financial Times reported Monday that the Jazan oil refinery, operated by Saudi Arabia's Saudi Aramco, was struck by Houthi attacks.
Yemen's National Resistance Forces, which are backed by the Saudi Arabian government, have launched counterattacks against the rebel group in an attempt to regain control of the country's capital city, San'a.
"In a low energy 24 hours the Middle East story has rumbled on as concerns about fresh US-Iran hostilities pushed oil prices higher still," Deutsche Bank's Jim Reid wrote in a Tuesday note. "In part, that followed the tanker attacks over the weekend, but it was also reported that the Houthi rebels had hit Saudi Arabian oil infrastructure yesterday."
Goldman Sachs is raising its forecast for oil, with Daan Struyven, head of commodities research, saying that Brent crude could top $120 a barrel if average output from the Persian Gulf in 2027 remains 4 million barrels below usual prewar levels.
-Nora Redmond