Iran must stop interfering in Palestinian affairs, president Mahmud Abbas said on Wednesday after talks with US Secretary of State Hillary Clinton.

"We are sending a message to the Iranians and others -- stop interfering in our affairs," he said. "They are interfering only to deepen the rift between Palestinians."

Abbas spoke on the same day that Iran's supreme leader Ayatollah Ali Khamenei called for world Muslims to join the Palestinian "resistance" against Israel at the start of a two-day summit in support of Hamas-run Gaza.

"The only way to save Palestine is resistance," Khamenei said in his address to open the global summit Tehran organised in aid of Gaza and the Palestinians.

"Support and help to Palestinians is a mandatory duty of all Muslims. I now tell all Muslim brothers and sisters to join forces and break the immunity of the Zionist criminals," Khamenei said.

The Islamic Republic is an enthusiastic supporter of the Islamist Hamas movement that has ruled Gaza since June 2007, when it booted forces loyal to the Western-backed Abbas out of the coastal strip.