Israeli forces and the pro-Iranian militia Hezbollah have engaged in massive exchanges of fire across the border between Israel and Lebanon, heightening fears of a wider escalation of the conflict in the region. Hezbollah said it had fired hundreds of rockets at Israel on Sunday in retaliation for the killing of one of its commanders in Beirut, as Israel said it carried out dozens of pre-emptive airstrikes in southern Lebanon. Hezbollah said more than 320 rockets had been fired at Israeli military bases. “Our military operation for today has been completed, thanks to God Almighty,” the Islamis…