At least eight people, including a child, were killed and over 2,750 people were killed in a cyberattack carried out by Israel on Tuesday.
A Hezbollah official, speaking on condition of anonymity, said the detonation of the pagers was the "biggest security breach" the group had been subjected to in nearly a year of war with Israel.
"We hold the Israeli enemy fully responsible for this criminal aggression," the group said in a statement, adding that Israel "will certainly receive its just punishment for this sinful aggression," Hezbollah said.
Health Minister Firas Abiad said a child was among those killed when pagers in numerous Lebanese regions exploded earlier on Tuesday.
Some 200 people are in critical condition, he said.
Most of the victims suffered injuries to the hand, while some were also injured in the face, abdomen and eyes, according to the minister.
Hezbollah said its members are among the injured, including fighters of the Radwan Force, an elite unit within the group. A source close to Hezbollah said high-ranking Hezbollah representatives have also been injured.
The group said it was looking into the cause of the detonations.
A Reuters journalist saw ambulances rushing through the southern suburbs of the capital Beirut amid widespread panic. Residents said explosions were taking place even 30 minutes after the initial blasts.
Groups of people huddled at the entrance of buildings to check on people they knew who may have been wounded, the Reuters journalist said.
There was no immediate comment from the Israeli military, which has been exchanging fire with Hezbollah since last October in parallel with its genocidal war on Gaza.
The detonations occurred in the southern suburbs of Beirut, a Hezbollah stronghold, as well as in the south of the country. Similar reports also came from neighboring Syria.
