Hand-held radios used by armed group Hezbollah detonated on Wednesday across Lebanon's south in the country's deadliest day since cross-border fighting erupted between the group and Israel nearly a year ago, stoking tensions after similar explosions of the militants' pagers the day before.

Communications devices used by Lebanon's armed group Hezbollah detonated late Wednesday afternoon across the country's south and in the southern suburbs of the capital Beirut, a security source and a witness said.