Israel has repeatedly targeted Hamas and Hezbollah officials in Lebanon since the Gaza war erupted almost a year ago.

Massive consecutive strikes hit Beirut's southern suburbs from late Saturday into Sunday, Reuters eyewitnesses said, sending booms across the city and sparking flashes of red and white for nearly 30 minutes visible from several kilometers away.

The crossing into Syria was being used by thousands to flee, but the Israeli military says Hezbollah were transporting weapons along it.