"There will definitely be a response to Israel's crimes, and this issue is not up for discussion. The decision is now on the battlefield and is determined by its circumstances and possibilities, we are looking for a real and very thoughtful, not formal response," Nasrallah said in an address in connection with the killing of of Sayyed Mohsen also known as "Fuad Shukr," and Hamas political leader Ismail Haniyeh.
Hezbollah will resume a "support front" for the Gaza Strip and attacks on Israel's military positions starting Friday morning, the leader added.
Earlier on Wednesday, Hamas confirmed that Haniyeh was killed in an Israeli attack on his residence in Tehran after he took part in the inauguration of newly elected Iranian president Masoud Pezeshkian.
Israel's airstrike on a southern suburb of Beirut, which targeted Hezbollah commander Fuad Shukr, has hit a residential building where families with children live, Hezbollah secretary general also said.
"The enemy's primary target, judging by their statements, was to murder our great commander [Shukr] ... A residential building in the Haret Hreik municipality in the southern suburb of Beirut was attacked, in which many people lived - families, women, men and children," Nasrallah said.
The Israeli strike came following an alleged rocket attack by Hezbollah on a soccer field in the village of Majdal Shams in the Israeli-occupied Golan Heights killed 12 Druze children and injured 20 others. Hezbollah denied the claim.
"The purpose of blaming the [Islamic] Resistance [other name of Hezbollah] for what happened in Majdal Shams is to fuel sectarian discord. Several countries asked Hezbollah not to respond to the Israeli strike on the suburb of Beirut," Nasrallah also noted.
Israel is thus trying to cause division between the Druze residents of the Golan Heights and Hezbollah, he added.