Israel's national security adviser predicted that the United States would get "involved" if the Gaza war escalated to the point where Iran and Hezbollah joined in on behalf of Hamas. Tzachi Hanegbi talked about support from US president Joe Biden, which included US naval deployments in the Mediterranean and a public warning to the Lebanese group. The US has also warned Iran to stay out of the fighting, he said.

"He is making clear to our enemies that if they even imagine taking part in the offensive against the citizens of Israel, there will be American involvement here," Tzachi Hanegbi said, adding, “Israel will not be alone ... A US force is here and it is ready.”

This comes as Israel's prime minister Benjamin Netanyahu called for broad international support in the country's war against Hamas.

"The world must stand united behind Israel to defeat Hamas," Benjamin Netanyahu said alongside visiting German chancellor Olaf Scholz.

"The savagery that we witnessed perpetrated by the Hamas murderers coming out of Gaza were the worst crimes committed against Jews since the Holocaust," Benjamin Netanyahu said, referring to the extermination of more than six million Jews by the Nazis.

More than 1,400 people have been killed in Israel and around 3,000 in Gaza since the conflict erupted, according to tolls by officials on both sides. Israel has bombarded the Gaza Strip with air strikes which have driven around half of the 2.3 million Gazans from their homes. Tel Aviv has also imposed a total blockade on the enclave, halting food, fuel and medical supplies, which are rapidly running out.

US president Joe Biden is set to visit Israel on Wednesday to show support for its war on Hamas after Benjamin Netanyahu agreed to let humanitarian aid reach besieged Gazans.

(With inputs from agencies)