Iran accused Israel of genocide and crimes against humanity against Palestinians during a virtual meeting Sunday with the 57-nation Organisation of Islamic Cooperation.
The OIC opened an emergency meeting over the heavy fighting between Israel and the Gaza Strip's militant Hamas rulers, the first major move among Mideast nations still grappling with how to address the conflict.
While the Arab League and organisations like the Saudi-based OIC have maintained their view that the Palestinians should have their own independent state, Israel recently has reached recognition deals with several of its members.
That, as well as the concerns of some nations over Hamas, has seen a somewhat-muted response to the attacks as opposed to the full-throated response of decades past.
Palestinian Foreign Minister Riad Malki of the Palestinian Authority, which administers autonomous enclaves in the Israeli-occupied West Bank, decried what he called Israel's "cowardly attacks" at the start of the meeting.
Iranian Foreign Minister Mohammad Javad Zarif accused Israel of "genocide and crimes against humanity".
"Make no mistake: Israel only understands the language of resistance and the people of Palestine are fully entitled to their right to defend themselves," Zarif said.
Zarif also called those with recognition deals naive, saying Israel designed them to divide the Muslim world.
"The massacre of Palestinian children today follows the purported normalisation," he said. "This criminal and genocidal regime has once again proven that friendly gestures only aggravate its atrocities."