In an interview with the TV channel, Sheikh Hassan Nasrallah said that the two Israeli soldiers captured by Hezbollah would not be released even "if the whole universe comes against us".
He said that the soldiers would be freed only as part of a prisoner exchange agreed through indirect negotiations.
Israeli aircraft had dropped 23 tonnes of explosives on a site in southern Beirut on Wednesday night, claiming that it was an underground bunker where Hezbollah leaders, possibly including Nasrallah, were meeting.
Hezbollah immediately denied that the building was a bunker and said that none of its members was hurt.
It said the site was a mosque that was under construction.
Nasrallah said: "I can confirm without exaggerating or using psychological warfare that we have not been harmed."
Aljazeera, which aired only excerpts of the interview, said it was taped earlier on Thursday.
The interviewer said the meeting took place amid tight security precautions but did not say where.
Nasrallah also denied claims by Israel to have destroyed half of Hezbollah's rocket arsenal, calling the claims "baseless".
He said: "Hezbollah has so far stood fast, absorbed the strike, retaken the initiative and made the surprises that it had promised, and there are more surprises."
He said that a Hezbollah defeat would be "a defeat for the entire Islamic nation".