The head of the International Atomic Energy Agency asked Israel to consider signing up to the Nuclear Nonproliferation Treaty, according to a report released Friday.A report by the Vienna-based watchdog said agency chief Yukiya Amano "invited Israel to consider to accede" to the treaty during a low-key visit last month.The report also contained a July 26 letter from Israeli Foreign Minister Avigdor Lieberman that pointed the finger at Iran and Syria as the Middle East's "real proliferation challenges."