BEIRUT, Sept 18 (Reuters) - 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 militants and Israel nearly a year ago, stoking tensions after similar explosions of the group's pagers the day before.

Explosions continued Wednesday in Lebanon, killing at least 20 people. The Lebanese government and Hezbollah blame Israel for the apparently coordinated attack. Israel’s defense minister said they are “at the start of a new phase in the war.

Israeli Defense Minister Yoav Gallant ushered in what he called a “new phase” in the war with regional Islamist groups and said troops would be diverted to the Lebanese border, an indication that long-held fears of a wider conflict may soon be realized.

In Lebanon, exploding pagers and booby-trapped walkie-talkies – believed to be set off by Israel – have rattled Hezbollah and captured the world’s attention. What do they portend?

Amid fears of an expanding war in the Middle East following mass detentions of bombs surreptitiously planted in Hezbollah communication devices, Israel continued its assault of the Iran-backed militia overnight.