The four senators gave the media conference ahead of a Wednesday vote on resolutions condemning the US weapons sales -- measures that are expected to fail given the large number of lawmakers who support Israel, a historic American ally.

The resolutions were put forth by progressive Senator Bernie Sanders, alongside several other Democrats.

The Vermont representative told reporters that "what is happening in Gaza today is unspeakable," pointing in particular to the deaths of tens of thousands of civilians in the Palestinian territory, as well as large-scale destruction of buildings and infrastructure.

"What makes it even more painful is that much of what is happening there has been done with US weapons and with American taxpayer support," he said.

The health ministry in Hamas-run Gaza says the death toll from the ongoing Israeli war has reached 43,972 people, the majority women and children. The United Nations considers the figures reliable.

The administration of President Joe Biden has steadfastly backed Israel while counselling restraint for more than a year.

"The United States of America is complicit in these atrocities," Sanders said. "That complicity must end and that is what these resolutions are about."

Democratic Senator Chris Van Hollen, also speaking at the media conference, questioned whether America's foreign policy and commitment to Israel had forced the United States to "be blind to the suffering before our very eyes?"