Israel and Hezbollah have exchanged fire - signalling an escalation in hostilities.

Israel says it pre-emptively destroyed thousands of rocket launchers across Southern Lebanon.

Meanwhile, Hezbollah says it fired 320 rockets and drones at Israel - in the first phase of a retaliatory attack for the killing of its leaders.

Otago University Middle East expert Leon Goldsmith told Ryan Bridge Hezbollah had wanted to wait until a ceasefire was reached in Gaza before acting.

He says the group had been under a lot of pressure to do something over the assassinations.

He says they called the operation Arbaeen which is Arabic for 40 days.