Israel pounds Lebanon's Hezbollah after device explosions that killed 37

Israel said it pounded Lebanon's Hezbollah, just hours after the group's leader vowed retribution for deadly explosions that targeted its communication devices, killing 37 people and wounding thousands.

Hezbollah blamed Israel for the explosion of thousands of its operatives' pagers and radios in attacks that spanned two days this week. Israel has yet to comment on the attacks.

Speaking for the first time since the deadly device sabotage, Hezbollah leader Hassan Nasrallah vowed on Thursday that Israel would face retribution.

Describing the attacks as a "massacre" and a possible "act of war", Nasrallah said Israel would face "just punishment, where it expects it and where it does not".

As he delivered his address, Israeli fighter jets roared over Beirut, their sonic booms shaking buildings and sending residents scrambling for cover.

Hours later, Israel's military said its jets hit "approximately 100 launchers and additional terrorist infrastructure sites, consisting of approximately 1,000 barrels" set to be fired immediately.

Lebanon's state-run National News Agency said Israel struck the south at least 52 times. It was one of the heaviest Israeli bombardments of south Lebanon since the border exchanges erupted last October.

Hezbollah meanwhile said it launched at least 17 attacks on military sites in northern Israel.

The device blasts and Thursday's barrage of air strikes came after Israel announced it was shifting its war objectives to its northern border with Lebanon where it has been trading fire with Hezbollah.

For nearly a year, Israel's firepower has been focused on Palestinian militant group Hamas in Gaza, but its troops have also been engaged in near-daily exchanges with Hezbollah militants.

International mediators have repeatedly tried to avert a full-blown war between Israel and Hezbollah and staunch the regional fallout of the war in Gaza.

Hezbollah maintains its fight is in support of Hamas, and Nasrallah vowed the attacks on Israel will continue as long as the war in Gaza lasts.

The cross-border exchanges of fire have killed hundreds in Lebanon, most of them fighters, and dozens in Israel, including soldiers. Tens of thousands of people on both sides of the border have been forced to flee their homes.