Spanish Prime Minister Pedro Sanchez on Saturday called for increased pressure "to halt the massacre in Gaza", speaking at an Arab League summit hours after Israel announced an intensified operation in the besieged Palestinian territory.
Sanchez, who has sharply criticised the Israeli offensive, said world leaders should "intensify our pressure on Israel to halt the massacre in Gaza, particularly through the channels afforded to us by international law".
He said his government planned a UN resolution demanding an International Court of Justice ruling on Israel's war methods.
The "unacceptable number" of war victims in Gaza violates the "principle of humanity", he said.
For its part, Italy's government on Saturday upped its exhortations to Israel to stop deadly military strikes in Gaza, with Foreign Minister Antonio Tajani saying: "Enough with the attacks."
"We no longer want to see the Palestinian people suffer," Tajani said during a trip to Sicily, in remarks relayed by his spokesman.
"Let's come to a ceasefire, let's free the hostages, but let's leave people who are victims of Hamas alone," he was cited as saying.
The Israeli military announced the early stages of an intensified operation in Gaza aimed at defeating Hamas, with rescuers in the besieged Palestinian territory reporting 10 killed Saturday in fresh strikes.
The stepped-up campaign came as the humanitarian situation in Gaza continued to worsen amid an Israeli aid blockade, with one of the territory's last functioning hospitals warning it was no longer able to treat seriously wounded patients due to shortages of supplies and a nearby attack that damaged the premises.
The army announced that it had begun the "initial stages" of the new offensive, part of "the expansion of the battle in the Gaza Strip, with the goal of achieving all the war's objectives, including the release of the abducted and the defeat of Hamas".
It said it had "launched extensive strikes and transferred forces to seize control of areas within the Gaza Strip".
The return to fighting has drawn international condemnation, with UN human rights chief Volker Turk on Friday denouncing the renewed attacks and what he described as an apparent push to permanently displace Gaza's Palestinian inhabitants as being "tantamount to ethnic cleansing".