Story highlights Iran's Supreme Leader has approved the P5+1 nuclear deal, his official website says

Ayatollah Ali Khamenei endorsed the deal's implementation with conditions

A letter to Iran's President says the deal will be void if future sanctions are imposed

(CNN) Iran's Supreme Leader has conditionally approved the nuclear deal signed between his country and six world powers in July.

Ayatollah Ali Khamenei's official website carries a letter from the Supreme Leader to Iranian President Hassan Rouhani endorsing the deal, subject to certain conditions.

The nuclear deal will be rendered void if any future sanctions are imposed on Iran by any country, or under any pretext -- including "human rights" and "alleged support of terrorism," according to the letter.

The letter lists a series of nine key conditions before saying, "The motion passed by the National Security Council ... adhering to the points mentioned, is approved."

Violation of agreement