Washington DC - President Joe Biden on Friday advised Israel against striking Iran's oil facilities, saying he was trying to rally the world to avoid the escalating prospect of all-out war in the Middle East.

Making a surprise first appearance in the White House briefing room, Biden added that Israel's Benjamin Netanyahu "should remember" US support for Israel when deciding on next steps.

"If I were in their shoes, I'd be thinking about other alternatives than striking oil fields," Biden told reporters, when asked about his comments a day earlier that Washington was discussing the possibility of such strikes with its ally.

Biden added that the Israelis "have not concluded how they're what they're going to do" in retaliation for a huge ballistic missile attack by Iran on Israel on Tuesday.

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The price of oil had jumped after Biden's remarks on Thursday.

Any long-term rise 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's unannounced appearance at the famed briefing room podium – the first of his presidency – comes at a tense time as he prepares to leave office, the situation boiling over in the Middle East, and political criticism at home over his handling of a recent hurricane that struck the US southeast.

Biden said he was doing his best to avoid a full-scale conflagration in the Middle East, where Israel is bombing Lebanon in a bid to wipe out the Iranian-backed militia Hezbollah.

"The main thing we can do is try to rally the rest of the world and our allies into participating... to tamp this down," he told reporters.

"But when you have [Iranian] proxies as irrational as Hezbollah and the Huthis [of Yemen] and it's a hard thing to determine."

Biden, however, had tough words for Netanyahu, with whom he has had rocky relations as he seeks to manage Israel's response following the October 7 Hamas attacks on Israel.

The Israeli premier has repeatedly ignored Biden's calls for restraint on Lebanon, and on Israel's war in Gaza, which has killed more than 40,000 Palestinians.

Biden deflected a question on whether he believed Netanyahu was hanging back on signing a Middle East peace deal in a bid to influence the US presidential election.

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"No administration has helped Israel more than I have. None, none, none. And I think Bibi should remember that," Biden said.

"And whether he's trying to influence the election, I don't know, but I'm not counting on that."

Biden said he had still not spoken to Netanyahu since the Iranian attack, which involved some 200 missiles, but added that their teams were in "constant contact."

"They're not going to make a decision immediately, and so we're going to wait to see when they want to talk," the US leader added.

Iran launched around 200 rockets in a direct missile attack on Israel on Tuesday, prompting Netanyahu to warn that Tehran would pay a hefty price.

Iran said it was in retaliation for the killing of Hassan Nasrallah, the leader of Hezbollah, among other aggressions.