The apparent Israeli attack has killed at least 37 people and injured thousands more, reports Justin Salhani from Beirut.

When streams of bloodied people converged on Lebanon's hospitals on Tuesday, it was a test of whether the crisis-hit health sector could cope with a mass casualty event like what could be expected in a wider war with Israel.

Another wave of blasts was reported a day after at least a dozen people were killed and thousands were wounded when pagers carried by members of Hezbollah detonated almost simultaneously.