Iran's foreign minister says he has been told by the country's top leader to control his temper during nuclear talks with Western diplomats.

Mohammad Javad Zarif tells Iran's Shargh daily newspaper Saturday that he has often raised his voice during meetings with U.S. Secretary of State John Kerry — sometimes so much that Zarif's concerned bodyguards would enter the room.

Zarif said Ayatollah Ali Khamenei, who has the final say on all state matters in Iran, told him to speak softly and with a smile — the same as he would in public.

Iran and the world powers - the U.S., Russia, China, Britain, France and Germany - hope to reach a rough deal on Iran's disputed nuclear program by March and a final agreement by June 30.