Iran's Supreme Leader Ayatollah Ali Khamenei called on Muslim states to cease oil and food exports to Israel, demanding an end to its bombardment of the Gaza Strip, state media reported.
"The bombings on Gaza must stop immediately. The path of oil and food exports to the Zionist regime should be stopped," Khamenei told a group of students in Tehran, according to Iranian state media.
Israel has waged its most ferocious and indiscriminate bombing of Gaza in 70 years, killing over 8,700 people, with almost half being children.
It has shelled hospitals, refugee camps and places of worship and imposed a "complete siege" on the territory, cutting off access to water, fuel and food for Gaza's 2.3 million people.
Israel has also gone on to cut off internet and phone access in Gaza, plunging the territory into a telecommunications blackout.
Iran's clerical rulers have warned Israel of an escalation if it failed to end violence against Palestinians, with authorities indicating Tehran-backed proxies in the Middle East were ready to act.
Backing the Palestinian cause has been a political pillar of the Islamic Republic since the 1979 Islamic Revolution with Iran fashioning itself as a leader in the Muslim world.
Khamenei, Iran's top authority, said the United States was complicit in Israel's "recent crimes against Palestinians".
Iran and Israel are regional arch-foes, with Tel Aviv accusing Tehran of financially backing Hamas.
"The Islamic world should not forget that in the crucial issue of Gaza, those standing against the oppressed Palestinian nation were the United States, France and Britain," Khamenei said to chants of "Death to Israel" and "Death to America".
"One of the shameless acts of the West is accusing Palestinian fighters of terrorism," he continued.
(Reuters and The New Arab Staff)