Iran's supreme leader Ayatollah Ali Khamenei on Friday warned the Palestinians against renewed peace talks with Israel, saying they would be "detrimental" to their cause.

The US-mediated talks will force "the Palestinians to relinquish their rights," Khamenei told worshippers in Tehran University after Eid al-Fitr prayers marking the end of the holy month of Ramadan.

His remarks came a day after the US State Department said Palestinian and Israeli negotiators would resume talks on ending their long-standing conflict on August 14 in Jerusalem.

Both sides have already agreed to try to resolve their differences within nine months.

The talks, restarted last month in Washington mediation, will also "encourage the aggressors to increase their aggression and suppress the rightful resistance of the Palestinians," said Khamenei, who has the final say on Iran's foreign policy.

Dismissing the talks as "the doing of the arrogance" -- an allusion to Iran's arch-foe the United States -- he said the result would "definitely be detrimental" to the Palestinians.

Iran, a major regional supporter of the Islamist Hamas movement that rules the Gaza Strip, does not see eye to eye with the Palestinian Authority.

The Islamic republic has repeatedly voiced opposition about talks focusing on a two-state solution, saying the Jewish state would never agree to withdraw from "occupied lands".

Khamenei on Friday also called on the Muslim world to condemn Israel's "oppressive" actions against Palestinians.

"The Muslim world must not back down from its support for Palestine, and it should condemn the oppressive action of fierce Zionist wolves and their international supporters," he said.