Iran won’t negotiate with world powers over its disputed nuclear program if under military threat, Iranian Supreme Leader Ayatollah Ali Khamenei said Wednesday, reflecting his wariness over long-running nuclear talks amid tensions in Middle Eastern seas.

In a speech delivered to a group of teachers in Tehran, Mr. Khamenei, who has final say over most matters of state in Iran, said he didn’t approve of any negotiations “under the ghost of a threat,” according to his official website.

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