Mr Nasrallah said his organisation had every right to seize an Israeli agent caught spying on Lebanese territory.
The Hezbollah leader, Sheikh Hassan Nasrallah, has said that an Israeli being held by his guerrillas was lured into Lebanon and then kidnapped after flying into the country on a forged foreign passport.
Mr Nasrallah said his organisation had every right to seize an Israeli agent caught spying on Lebanese territory.
At a news conference in Beirut, Sheikh Hassan Nasrallah said the Israeli had been lured here in an elaborate sting operation.
He said the man had flown from Brussels to Lebanon on a forged foreign passport, believing he was about to meet a senior Hezbollah contact who would enable him to penetrate and spy on the guerrilla organisation.
It is, he said, the legitimate and legal right of the resistance to capture and hold him.
Israeli denial
Israel maintains that the man is not a spy but a 54-years-old independent businessman called Elhanan Tennenbaum.
It has conceded that Mr Tennenbaum may, like many Israeli men, be an officer in the army reserve.
This is the fourth Israeli that Hezbollah has seized in little more than a week.
The militant Islamic organisation, condemned by Israel and the United States as terrorist group, is also holding three soldiers captured on the Lebanese border.
Hezbollah has said it wants to exchange the men for nineteen Lebanese prisoners being held in Israeli jails and possibly for hundreds of Palestinian detainees too.