By Alexander Cornwell, Parisa Hafezi and Jeff Mason TEL AVIV/DUBAI/WASHINGTON (Reuters) -Iranian missiles struck Israel's Tel Aviv and the port city of Haifa before dawn on Monday, destroying homes and fuelling concerns among world leaders at this week's G7 meeting that the confrontation could lead to a broader regional conflict.

Israel and Iran exchange missile attacks for a third day; nuclear sites hit, death tolls rise, airspace shut, U.S. warns Tehran against retaliation.

Iran launched a heavy barrage of missiles at Israeli targets early Monday, hitting Tel Aviv and Haifa and igniting large-scale fires and destruction, in what regional sources described as the most intense assault to date.