TEHRAN. Iran’s nuclear energy chief struck out at the head of the U.N. atomic watchdog yesterday, suggesting he had made a “dangerous” mistake by criticizing Iran for barring some nuclear inspectors. The comments by Ali Akbar Salehi, reported by the official IRNA news agency, were a further sign of worsening relations between Iran and the International Atomic Energy Agency since Yukiya Amano became IAEA Director General in December.