• Oil market analysts worry Israel could strike Iran's oil industry.
• Such an attack could lead to Iran disrupting oil supplies through the Strait of Hormuz, analysts say.
• The Strait of Hormuz is one of the world's most sensitive choke points for oil exports.

U.S. crude oil jumped more than 3% on Monday, as the market waited for Israel to strike Iran.

Oil prices spiked last week on fears that Israel could hit Iran's oil industry in retaliation for Tehran's ballistic missile attack.

U.S. benchmark West Texas Intermediate surged 9.09% last week for the biggest weekly gain since March 2023. Global benchmark Brent jumped 8.43% for the largest weekly advance since January 2023.

Here are Monday's closing energy prices:

• West Texas Intermediate November contract: $77.14 per barrel, up $2.76, or 3.71%. Year to date, U.S. crude oil has gained more than 7%.
• Brent December contract: $80.93 per barrel, up $2.88, or 3.69%. Year to date, the global benchmark is ahead about 5%.
• RBOB Gasoline November contract: $2.1538 per gallon, up 2.77%. Year to date, gasoline has advanced more than 2%.
• Natural Gas November contract: $2.746 per thousand cubic feet, down 3.78%. Year to date, gas is ahead more than 9%.

President Joe Biden on Friday discouraged Israel from striking Iranian oil facilities, after prices jumped about 5% a day earlier when the president suggested the U.S. was discussing the possibility of such an attack. Biden has also said he opposes Israel hitting Iran's nuclear facilities.

It's still unclear what form Israeli retaliation will take, said Helima Croft, head of global commodity strategy at RBC Capital Markets. The impact on the oil market would be significant if Israel struck Kharg Island, through which 90% of Iran's crude exports pass, Croft said.

"We do really have to see what the Israelis hit, what would the Iranian response mechanism be" Croft told CNBC's "Worldwide Exchange" on Monday. "But certainly we have not been closer to a regional war in a long time."

The market right now is only pricing in the possibility of Israel striking Iran's oil facilities but that is not the worst-case scenario, Alan Gelder, vice president of oil markets at Wood Mackenzie, told CNBC's "Squawk Box Europe" on Monday.

The worst-case scenario is a disruption in the Strait of Hormuz, through which 20% of the world's crude exports flow, Gelder said. Iran might target the strait in response to an Israeli strike, which would have a far more dramatic effect on crude prices, the analyst said.

The war between Israel and Hamas in Gaza has now ground on for a year with no end in sight. The conflict has increasingly escalated into a multifront war in the Middle East. Israel is battling Hezbollah in Lebanon and has struck Houthi militants in Yemen, in relation for rocket attacks by those groups.

Hamas, Hezbollah and the Houthis are allied with Iran. The war in the Middle East has not led to a disruption of crude supplies so far, but analysts warn the risk is rising the longer the conflict continues.