US national security adviser Jake Sullivan said on Monday that President Joe Biden's administration does not view the killings of Palestinians in Gaza by Israel in its war with Hamas as genocide.

Sullivan said the United States wants to see Hamas defeated. He also said that Palestinians caught in the middle of the war were in "hell" and that a major military operation by Israel in Rafah would be a mistake.

"We do not believe what is happening in Gaza is a genocide. We have been firmly on record rejecting that proposition," Sullivan told reporters at the White House.

Sullivan expressed concern about reports of Israeli settlers attacking a humanitarian aid convoy on its way to Erez Crossing in northern Gaza, the second such incident in less than a week.

"It is a total outrage that there are people who are attacking and looting these conveys," Sullivan said. "It is completely and utterly unacceptable behavior."

Biden, who is running for re-election this year, has faced heavy criticism from his own supporters domestically for his support of Israel; some of those critics have accused Israel of committing genocide. More than 35,000 Palestinians in Gaza have died, according to Gaza health officials.

Biden has sought to influence Prime Minister Benjamin Netanyahu's approach to the war, but Israel is a sovereign, democratic nation that ultimately makes its own decisions, Sullivan said.

"The prime minister doesn't have to answer to us. He's got to answer to the Israeli people," Sullivan said.

Reiterating a comment made by Biden on Saturday, Sullivan said there could be a ceasefire in Gaza now if Hamas would release hostages. The world should be calling on Hamas to return to the negotiating table and accept a deal, Sullivan said.

The United States is working urgently for a ceasefire and hostage-release deal, Sullivan said. He said he could not predict when or if such a deal would be sealed.