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 battle between the two old enemies could lead to a broader regional conflict.

Dozens of others were injured overnight across Israel, the authorities said. Israel was striking military sites in Iran and the four-day-old conflict showed no sign of slowing.

It follows daytime attacks from both sides, with Israeli strikes in Tehran continuing and Iran firing more missiles towards Israel.

CONFLICT ENTERS FOURTH DAY: Israel and Iran have begun a new round of attacks, as the conflict between the two heavily armed rivals enters its fourth day.

Hundreds of civilians, mostly in Iran, have been killed by dueling airstrikes despite international pleas for de-escalation.

Israel and Iran have traded more missile attacks despite international calls for a halt to the fighting, with neither country showing signs of backing down as the conflict between the regional foes raged for a third day.

Israel targeted nuclear and military sites in Iran in airstrikes early Friday morning.The strikes are a major escalation that threatens to expand into a wider regional conflict.These are five key questions as the conflict continues.

Israel warns "Tehran will burn" if Iran continues firing missiles, while state media say 60 people have been killed in a strike on Iran's capital.