US Democrats question arms to Israel over Gaza concerns

US President Joe Biden's administration faced growing calls from his fellow Democrats on Wednesday to push Israel to ease the devastating humanitarian crisis in Gaza, with some saying they may try to stop military assistance if conditions for civilians do not improve.

"We need to use all the leverage we've got. The administration has not used the leverage it has to date. I don't know how many more kids have to starve before we use all the levers of our influence here, but they really need to do more," Senator Chris Van Hollen, a Democratic member of the Foreign Relations Committee, told reporters.

Van Hollen and other lawmakers have called upon the administration to hold back military assistance to Israel if Prime Minister Benjamin Netanyahu's government does not take steps such as opening crossings into Gaza for aid shipments.

The White House did not immediately respond to a request for comment. The administration has so far declined to put conditions on assistance for Israel.

"How many more homes and shops and schools and child-care centres and hospitals must be destroyed before we say to Prime Minister Netanyahu: Enough?" Democratic Senator Pete Welch said in a Senate speech on Tuesday.

The comments came as Biden prepared to make his annual State of the Union address in Congress when he lays out policy priorities to his largest television audience of the year.

The Israeli offensive in Gaza has displaced most of the enclave's 2.3 million people and led to critical shortages of food, water and medicine.

Some voters - particularly Muslim Americans - have been responding with protest votes in primary races as Biden runs for re-election in November by marking their ballots "uncommitted."

Van Hollen noted that US law bars weapons sales to countries that block humanitarian aid and said he and other lawmakers may try to block new weapons sales to Israel if its government does not address the crisis.

The US Arms Export Control Act gives Congress the right to stop a foreign major weapons sale by passing a resolution of disapproval. Although no such resolution has both passed Congress and survived a presidential veto, an angry debate on the issue could embarrass the White House.

Washington also has briefed Israel on a new national security memorandum that reminds countries receiving U.S. weapons to stick to international law.

Separately, dozens of House of Representatives Democrats released a letter to Biden on Wednesday expressing "our deep sense of urgency and alarm" about the hardships faced by civilians in Gaza.

Since 7 October, more than 30,700 people have been killed in Israel's indiscriminate military campaign on Gaza.