GAZA/JERUSALEM: Israel bombarded the Gaza Strip as it prepared for a ground invasion it says is aimed at annihilating the Palestinian group Hamas as Russia warned the conflict could spread beyond the Middle East.

In besieged Gaza humanitarian supplies were critically low, as world powers failed to agree on a lull to the fighting to deliver aid, and residents buried the dead in mass graves as the civilain toll mounted.

U.S. President Joe Biden, in remarks looking beyond the war, said on Wednesday that the future should include Israeli and Palestinian states side by side.

"Israelis and Palestinians equally deserve to live side by side in safety, dignity and in peace," Biden said at a joint press conference in Washington with visiting Australian Prime Minister Anthony Albanese.

Biden said he believed one reason Iranian-backed Hamas attacked southern Israel on Oct. 7, killing at least 1,400 people and taking scores of hostages, was to prevent normalising relations between Israel and Saudi Arabia.

Russian President Vladimir Putin warned the conflict could spread beyond the Middle East and said it was wrong that innocent women, children and old people in Gaza were being punished for other people's crimes.

"Our task today, our main task, is to stop the bloodshed and violence," said Putin in a meeting with Russian religious leaders of different faiths, according to a Kremlin transcript.

"Otherwise, further escalation of the crisis is fraught with grave and extremely dangerous and destructive consequences. And not only for the Middle East region. It could spill over far beyond the borders of the Middle East."

Reflecting concerns the Gaza war may spread, the Wall Street Journal reported that Israel had agreed to delay invading Gaza until U.S. air defence systems can be placed in the region, as early as this week, to protect American forces.

Asked about the report, U.S. officials told Reuters that Washington has raised its concerns with Israel that Iran and Iranian-backed Islamist groups could escalate the conflict by attacking U.S. troops in the Middle East. An Israeli incursion into Gaza could be a trigger for Iranian proxies, they said.

Gaza's war has already sparked conflict beyond the Palestinian territories. Israeli warplanes struck Syrian army infrastructure on Wednesday in response to rockets fired from Syria, an ally of Iran. Israel has also targeted Syria's Aleppo airport and Iranian-backed Hezbollah in Lebanon.

Iran, Israel's arch-enemy, has sought regional ascendancy for decades and backs armed groups in Syria, Lebanon and elsewhere as well as Hamas. It has warned Israel to stop its onslaught on Gaza.

AID PROPOSALS FAIL IN UN SECURITY COUNCIL VOTES

At the United Nations, Russia and China vetoed a U.S.-drafted Security Council resolution calling for pauses in hostilities to allow food, water and medicine to be delivered to Palestinian civilians. The United Arab Emirates also voted no, while 10 members voted in favour and two abstained.

Russia made a rival proposal that advocated a wider ceasefire, but failed to win the minimum number of votes. Israel has resisted both, arguing that Hamas would only take advantage and create new threats to Gaza civilians.

As the death toll mounts in Gaza, Palestinians are burying the unidentified dead in mass graves, with a number instead of a name, residents say. Some families are using bracelets in the hope of finding their loved ones should they be killed.

Israeli retaliatory strikes have killed over 6,500 people, the health ministry in the Hamas-run strip said on Wednesday. Reuters has been unable to independently verify the casualty figures of either side.

Biden said on Wednesday he had "no confidence in the number that the Palestinians are using" for the death toll, but he did not say why he was skeptical.

In the U.S., the Council on American-Islamic Relations (CAIR) said it was "deeply disturbed" by Biden's comments on the Gaza figures, and called on the president to apologise.

INVASION PREPARATIONS

Israel has vowed to wipe out Hamas, which rules Gaza.

Prime Minister Benjamin Netanyahu said in a televised statement that Israel was "preparing for a ground invasion. I will not elaborate on when, how or how many."

Israeli tanks and troops are massed on the border with Gaza awaiting orders. Israel has called up 360,000 reservists.

International pressure is growing to delay any invasion of Gaza, not least because of hostages. More than half the estimated 220 hostages held by Hamas have foreign passports from 25 different countries, the Israeli government said. Many were believed to have had dual Israeli nationality.