The Pentagon is not backing off on its support for Israel, despite growing frustration by some U.S. lawmakers that Israel is crossing ethical lines as it goes after Hamas in Gaza.

During a U.S. Senate Armed Services Committee hearing Tuesday interrupted multiple times by protesters accusing Israel — and the United States — of having innocent blood on its hands, Defense Secretary Lloyd Austin pushed back.

Senator Tom Cotton, a Republican, asked Austin: "Is Israel committing genocide in Gaza?"

Austin replied: "Senator Cotton, we don't have any evidence of genocide."

But under repeated questioning, Austin acknowledged Israel’s military can and must do more to differentiate between Hamas militants and civilians.

"There’s no question that there have been far too many civilian casualties in this conflict,” he said.

Austin said he has warned his Israeli counterpart that a failure to allow the delivery of much more humanitarian aid to Gaza “would just create more terrorism.”

As for continued talk by Israel about an operation to root out Hamas in Rafah, the secretary of defense was blunt. “It cannot be what we’ve seen in the past in terms of the type of activities that we've seen in Gaza City and in Khan Yunis,” he said.

Not all lawmakers were satisfied with those answers. Some expressed frustration that Washington has been forced to step in.

"There's no reason the United States should have to build a pier in the eastern Mediterranean. There's no reason we should have to airdrop supplies,” said Senator Tim Kaine, a Democrat. "The pace of humanitarian aid is insufficient."

Other lawmakers put blame on Hamas. Austin agreed that the U.S.-designated terror group’s ongoing conduct continues to amount to war crimes.

The hearing was about President Joe Biden's budget request for the Department of Defense.