JERUSALEM/BEIRUT (Reuters) -Heavy Israeli airstrikes killed 12 people, including five Hezbollah fighters, in eastern Lebanon on Tuesday, a security source in Lebanon said, in what Israel said was a warning to the Iran-backed group against trying to re-establish itself.

Israeli military said it had begun striking targets belonging to Hezbollah's elite unit, the Radwan Force, in the Bekaa region of eastern Lebanon, as it accuses the Iran-backed Islamist group of seeking to rebuild its forces in violation of a ceasefire agreement.

Twelve people, including five Hezbollah fighters, were killed and eight others wounded Tuesday in Israeli strikes on the Bekaa Valley in eastern Lebanon, security sources and the official news agency reported.