The Israeli military said it struck the headquarters of Lebanese militant group Hezbollah in the southern suburbs of Beirut on Friday.
"The military carried out a precise strike on the central headquarters of the terrorist organisation Hezbollah in Dahiyeh," military spokesman Daniel Hagari said in a televised statement.
The headquarters "served as the epicentre of Hezbollah's terror".
The strike came soon after Israeli Prime Minister Benjamin Netanyahu vowed to continue targeting Hezbollah in Lebanon.
"We will continue degrading Hezbollah until all our objectives are met," he told world leaders at the UN.
The headquarters is "located under residential buildings in the heart of Dahiyeh in Beirut," Rear Admiral Hagari said.
Videos and photos shared online showed piles of smoke billowing from buildings from the explosions.
The strikes come as Netanyahu delivered a speech at the UN General Assembly vowing to continue the Israeli military's "objectives" in Lebanon, and in Gaza.
Before Netanyahu took to the podium, several officials could be seen staging a walk-out.
More than 700 people in Lebanon have been killed this week by Israeli strikes after Tel Aviv dramatically escalated strikes chiefly on the country's south, claiming it is targeting Hezbollah's senior commanders and military.
The intensified strikes have triggered large numbers of Lebanese fleeing their towns and villages, and seeking refuge elsewhere in the country and in neighbouring nations.
The UN warned that a "catastrophic" intensification of Israeli attacks had left Lebanon facing its deadliest period in years, with its hospitals overwhelmed by casualties.