Growing concerns that Israel could attack Iranian oil production facilities pushed crude oil futures more than 5% higher Thursday.

Israel had vowed retaliation after a missile attack on its soil by Iran earlier this week. Any Israeli action against Iran could potentially disrupt oil supply from the world's ninth-largest oil producing nation.

"There have been suggestions that Israel could target Iranian oil facilities, which would have the potential to push oil prices significantly higher depending on the scale of the attack," Warren Patterson, ING's Head of Commodities Strategy wrote in a note Thursday.

Brent crude futures breached the $77/barrel level while U.S. benchmark Western Texas Intermediate (WTI) broke above the $73/barrel mark. Both were trading at their highest levels since early September.

Fears of Broader Supply Disruptions

Goldmans Sachs analysts said that investors will be looking out for of supply disruptions beyond the "potential downside risks to Iran supply" affecting oil prices. That could include disruptions in oil supply coming through the Red Sea and interruption of trade through the Strait of Hormuz.

These worries are more than offsetting any news or data that could push prices lower, such as Libya resuming production and exports of oil and an increase in U.S. oil inventories.

Some of the interest from investors may also stem from betting on oil as a hedge.

"To manage election and geopolitical uncertainty, we recommend capital preservation strategies, diversification, and exposure to hedges such as gold and oil," said UBS Global Wealth Management Chief Investment Officer Mark Haefele.

Oil Stocks Gain With Rising Prices

Oil-related stocks have been surging in line with the increase in crude oil prices.

The S&P 500 Energy (SPN) sector was up 1.5% Thursday afternoon and was among the few sectors rising on an otherwise down day for stocks. It's risen nearly 6% this week and is on track for its best week of the year. With this week's gains, SSGA's Energy Select Sector SPDR Fund (XLE), a $36 billion exchange-traded fund that tracks the index, is up 13% this year.

Shares of several oil and oilfield services companies, including Marathon Petroleum (MPC), Diamondback Energy (FANG), Occidental Petroleum (OXY) and Halliburton (HAL) were all posting big gains Thursday.