As Israel-Iran Hostilities Flare Up, Ball In Tehran's Court Now

An explosion was heard early Friday in Isfahan, Iran's third-biggest city, Fars news agency reported.

Israel launched a retaliatory strike on Iran following last week's missile and drone barrage from Tehran, according to two US officials, though media from both countries appeared to downplay the severity of the incident.

An explosion was heard early Friday in Isfahan, Iran's third-biggest city, Fars news agency reported. Nuclear facilities located there are safe, state television and the United Nations' nuclear watchdog said.

Neither the Iranian nor Israeli government has confirmed there was a strike by Israel. The Jewish state rarely comments on specific military actions linked to Iran.