Biden told reporters at the White House however that he was not expecting Israel to launch any retaliation for Tehran's missile barrage on Israel before Thursday at least.

When asked by a reporter if he supported Israel striking Iran's oil facilities, Biden said "we're discussing that. I think that would be a little... anyway."

Oil prices jumped five percent over concerns about the Middle East after Biden spoke.

A rise in oil prices could be hugely damaging for Biden's Vice President Kamala Harris as the Democrat confronts Republican former president Donald Trump in a November 5 election where the cost of living is a major issue.

Biden said he did not expect any immediate action from Israel -- even if Israeli Prime Minister Benjamin Netanyahu has recently paid little heed to calls for restraint as he targets the Iran-allied Hezbollah militia in Lebanon.