US President Joe Biden has delivered a rare address to Americans from the Oval Office, urging them to get behind a multibillion-dollar plea for spending for Israel and Ukraine.

Biden sought to link Hamas militants in the Gaza Strip, who have attacked Israel, to Russian President Vladimir Putin, whose forces invaded Ukraine.

“Hamas and Putin represent different threats, but they share this in common: They both want to annihilate a neighbouring democracy,” he said on Friday (AEDT).

“History has taught us that when terrorists don’t pay a price for their terror, when dictators don’t pay a price for their aggression, they cause more chaos and death, and more destruction.

“They keep going, and the cost and the threats to America and the world keep rising.”

While Biden didn’t exactly say how much he was seeking in extra funding, he is expected to be asking for $US100 billion ($158 billion) over the next year.

He spoke about 20 hours after returning from a whirlwind trip to Israel to show US solidarity after the October 7 attack by Hamas militants who launched attacks from Gaza and killed 1400 people in southern Israel.

Biden’s message – only his second live address from the Oval Office since he became President – carried some urgency.

Israel is poised to launch a ground offensive to root out Palestinian Hamas militants from Gaza and tensions are at a fever pitch after a deadly blast at a Gaza hospital.

“You see Gaza now from a distance, you will soon see it from inside. The command will come,” Israeli Defence Minister Yoav Gallant told soldiers gathered at the Gaza border earlier on Friday.

Biden said Israel was not responsible for the hospital blast, as Hamas officials had asserted, but said: “We can’t ignore the humanity of innocent Palestinians who only want to live in peace and have opportunity.”

Biden voiced concern that some Americans were asking, “Why does it matter to America” that the US support the wars?

“I know these conflicts can seem far away,” he said.

But he said America’s adversaries were watching how both conflicts played out and could stir up trouble elsewhere in the world depending on the outcome.

“Making sure Israel and Ukraine succeed … is vital for America’s national security,” he said.

“We’re stronger than ever before. America is a beacon to the world, still. Still.”

“We can’t let petty partisan, angry politics get in the way of our responsibility as a great nation.”

He spoke against a backdrop of political chaos in Washington, as Republicans who control the House of Representatives have struggled to settle on who will lead them as speaker after ousting Kevin McCarthy from that job.

Biden requested emergency spending for Israel, Ukraine and Taiwan and security along the porous US border with Mexico.

It may include $US60 billion ($95 billion) for Ukraine and $US10 billion ($16 billion) for Israel, sources said, as well as billions for Asia and US border security.

By lumping the priorities together in one package, Biden is testing whether Republican lawmakers can be persuaded to set aside their opposition and go along with spending on Ukraine, whose 20-month-old war with Russia has absorbed billions of dollars already in US weapons with no end in sight.

Any funding measure must pass both the Democratic-led US Senate, where additional aid has bipartisan support, and the Republican-led House, which has not had a Speaker for 17 days.

Conservative Jim Jordan, an ally of former President Donald Trump, vowed to continue his bid for House Speaker after failing to win majority support among Republicans.

House Republican lawmakers in recent weeks nearly brought government to a halt over chronic budget deficits and $US31.4 trillion ($49.6 trillion) in debt, threatening to slash government spending across the board.

About four in 10 respondents in a Reuters/Ipsos poll conducted last week said the US should support Israel’s position in the conflict when given a range of options. Nearly half said Americans should remain neutral or not be involved.

In a separate Reuters/Ipsos poll earlier this month, roughly the same proportion agreed with a statement that Washington “should provide weapons to Ukraine.”

-with AAP