Biden sought to link Hamas militants who attacked Israel in the Gaza Strip 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.

Biden 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 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.

Biden said Israel was not responsible for the 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 are asking, “Why does it matter to America” that the United States 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.

The US president 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 that US officials say will total roughly $US100 billion ($A158 billion) over the next year for Israel, Ukraine and Taiwan and security along the porous US border with Mexico.

It may include $US60 billion ($A95 billion) for Ukraine and $US10 billion ($A16 billion) for Israel, sources said beforehand, 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 $US31.4 ($A49.6) 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.”