An Israeli strike late on Thursday in the heart of Beirut killed 22 people and injured more than 100, Lebanese authorities said. The target was a senior Hezbollah official - Wafiq Safa - who survived, according to three security sources.
The White House said the US was deeply concerned by reports that Israeli forces fired on UN positions and was pressing Israel for details.
Israel says its campaign in Lebanon aims to secure the return home for tens of thousands of people forced to leave northern Israel due to Hezbollah rocket fire over the last year.
The Middle East remains on high alert for further escalation in the region, awaiting Israel's response to an Iranian missile strike on Oct. 1.
