Oil stretched gains on Wednesday as investors' worries on crude and fuel supplies spiked, in response to strikes by Ukraine on Russian refineries and the possibility of an expansion of the Israel-Hamas conflict to encompass Iran more directly.

Brent crude added 0.19%, to $89.09 per barrel, while US WTI rose by 0.08% to $85.22 per barrel.

Both advanced by 1.7% the earlier session, touching a peak not seen since October.

Prices ticked up as a result of the threat posed by a Ukrainian drone strike on a second Russian refinery to shut down even more of the nation's processing capacity and reduce the amount of gasoline and diesel produced. Russia is one of the top three producers of oil in the world and a major supplier of petroleum products.

Additionally, investors fear that Iran's vengeful response to Israel's attack on Monday, which claimed the lives of high-ranking military officers, may cause supply interruptions in the vital Middle East producing region.