Oil prices rose more than 5% in trading on Tuesday after Iran began a ballistic missile attack on Israel, before those gains recurred at settlement.
The benchmark U.S. crude futures recently traded at around $71 a barrel, close to their level a week ago.
Oil prices have stabilized near multi-year lows in recent weeks despite a series of Israeli strikes in Lebanon targeting the Tehran-backed armed group Hezbollah. The growing campaign against Hezbollah has reignited fears of a direct confrontation between Israel and Iran.
Until this point, energy markets have been relatively optimistic in the face of months of escalating violence in the Middle East.
Brent crude futures for December delivery rose $1.86, or 2.59%, to $73.56 a barrel at settlement.
U.S. West Texas Intermediate crude futures for November delivery also rose $1.66, or 2.44%, to $69.83 a barrel.
The possibility of an armed conflict between Iran and Israel has raised concerns about the stability of oil supplies from the Middle East. Market watchers are reacting to the growing risk of supply outages, which could intensify if conflict spreads, which could lead to higher prices.