Tehran (AFP) - The United States remains Iran's "number one enemy" despite a recent nuclear deal with world powers, the chief of Tehran's top clerical body said Tuesday, Iranian media reported.

The Assembly of Experts is among Iran's most influential institutions, comprising 86 elected clerics who appoint and can dismiss the country's supreme leader, led by ultraconservative Ayatollah Mohammad Yazdi.

The nuclear agreement should not "change our foreign policy" of opposition to the United States, "our number one enemy, whose crimes are uncountable", Yazdi said in a speech opening the annual two-day assembly meeting.

"The US and Israel are the source of the situation in the region and (their) goal is to protect the Zionist regime in the Middle East," he was quoted as saying, blaming the two countries for the conflicts in Syria, Iraq and Yemen.

Iran's President Hassan Rouhani, who as a cleric is also a member of the Assembly of Experts, took office in 2013 and has since reached out to the West for better relations.

The nuclear agreement reached on July 14 with six world powers -- Britain, China, France, Russia, the United States and Germany -- has helped revive Iran's political stating with the European countries.

Several high-level European delegations have visited Tehran since the deal.

But despite the nuclear talks and the intricate role US Secretary of State John Kerry played in getting the deal across the line, there is currently little prospect of normalisation between Iran and the United States.

The two severed ties in 1980 after the hostage taking of US diplomats by Islamist students.

By AFP