Israel is attempting a risky strategy, increasing the intensity of its attacks in an attempt to force Hezbollah to back down, while raising the chances of an aggressive response that devolves into a land war.

The absence of a full-blown war in Lebanon has been touted as a core U.S. achievement, but now Washington’s grip on the crisis appears more tenuous than ever.

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.

Israel hit a Beirut suburb with an airstrike Sept. 20, not long after Hezbollah pounded northern Israel with 140 rockets. This follows Israel striking hundreds of Hezbollah rocket launchers on Sept. 19,

Lebanon and Hezbollah have blamed Israel for the attacks on Tuesday and Wednesday that killed 37 people and wounded around 3,000, although Israel has not directly commented on the attacks, which security sources say were probably carried out by its Mossad spy agency.

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?