DUBAI (AFP) - The UN atomic watchdog chief warned on Saturday that an attack on Iran over its controversial nuclear programme would turn the region into a fireball, as Tehran rejected any Israeli strike as "impossible." Mohamed ElBaradei also warned that he would not be able to continue in his role as International Atomic Energy Agency (IAEA) director general if the Islamic republic were attacked. His stark comments came as Iran stressed yet again that it will not negotiate with world powers over its nuclear programme if it is required to suspend its controversial uranium enrichment. "A military strike (against...