Crude futures rose by 4pc in early trading on Monday, supported by concerns over wider fallout from Gaza-based Islamist group Hamas' large-scale attack on Israel.
The front-month December Ice Brent contract rose by as much as 4.2pc to a high of $88.15/bl when markets opened in Asia, up by $3.57/bl from its settlement on 6 October. November Nymex WTI futures rose by as much as 4.5pc to $86.48/bl.
Over 700 Israelis were killed in the unprecedented attacks, the Israeli government said, while reports put the death toll in the Gaza Strip at over 400. Israel is "at war," prime minister Benjamin Netanyahu said on 7 October.