“We hold the Israeli enemy fully responsible for this criminal aggression that also targeted civilians,” Hezbollah said, adding that Israel will ”will certainly receive its just punishment for this sinful aggression."

Hezbollah chief Hassan Nasrallah will speak at 5:00 pm (1400 GMT) on Thursday in a speech addressing "the latest developments," the group said in a statement on Wednesday .

Hezbollah said two of its fighters were among the dead. Later media reports said the son of the Hezbollah MP Ali Ammar also died in the explosions.

Tehran's ambassador in Beirut was wounded but his injuries were not serious, Iranian state media reported.

The Lebanese group also promised that it "will continue, as in all the past days, its blessed operations to support Gaza."

"This path is ongoing and separate from the difficult reckoning that the criminal enemy must await for its massacre on Tuesday," the group said in a statement issued on Telegram.

There was no immediate comment from the Israeli military on the wave of explosions, which came just hours after Israel announced it was broadening the aims of the war in Gaza to include its fight against Hezbollah along the country's border with Lebanon.

A Hezbollah official, speaking on condition of anonymity, told Reuters that the incident was the "biggest security breach" for the group in nearly a year of conflict with Israel.

The blasts were mainly in areas where the group has a strong presence, particularly a southern Beirut suburb and in the Beqaa region of eastern Lebanon, as well as in Damascus, Lebanese security officials and a Hezbollah official told AP.

A Hezbollah source said they believed the attack was in response to an alleged assassination attempt by the Lebanese group on a former top Israeli defence official, revealed on Tuesday by the Israeli Shin Bet security agency.

It accused Hezbollah of attempting to kill a former security official using a claymore anti-personnel mine that could be detonated remotely, publishing photos of a dismantled bomb and wiring wrapped in tape that it claimed showed the attack was prevented in its “final stages”.

Lebanese Information Minister Ziad Makary condemned the detonation of the pagers - handheld devices that Hezbollah and others in Lebanon use to send messages - as an "Israeli aggression."