The comments illustrate the fragile situation along the frontier since Israel and Iranian-backed Hezbollah fought a bitter, six-week war in the summer of 2006. The conflict ended in a U.N.-brokered truce but officials on both sides of the border have warned hostilities could resume.
"I tell the holy warriors of the Islamic resistance to be ready for a day when, if war is imposed on us, your command might ask you to control the Galilee area," Hezbollah leader Sheik Hassan Nasrallah said in a televised speech Wednesday. The Galilee refers to northern Israel, near the border with Lebanon.
Responding to Nasrallah's threat, Israeli Prime Minister Benjamin Netanyahu said, "I have news for you. He won't. The last thing anyone should have is any doubt about is Israel's determination to defend itself and defend its people."
He called Hezbollah an Iran-backed "terror organization" that has taken control of Lebanon.
Hezbollah forced the collapse last month of Lebanon's unity government, led by pro-Western factions, and now has an opportunity to have a greater role in the new one. Hezbollah's favored candidate, Najib Mikati, was named the new prime minister, though he is struggling to form a new Cabinet.
On Tuesday, Israeli Defense Minister Ehud Barak toured his military's northern command and told soldiers that the quiet along the frontier might not last.
"This is not forever and it could under certain conditions deteriorate, and then you will have to be called on again, with everything you learned in training," he said. "Today the units are better trained and more prepared but there is always more to be done and you need to be ready for every test."
The 34-day war in 2006 between Hezbollah and Israel left 1,200 Lebanese and 160 Israelis dead. The war was sparked when Hezbollah fighters snatched Israeli soldiers in a cross-border raid. During the fighting, Israel heavily bombarded southern Lebanon and its troops pushed across the border. Hezbollah fired thousands of rockets into Israel, but its fighters didn't cross into northern Israel.
Nasrallah's speech was broadcast to a rally commemorating the killing of three Hezbollah leaders, including the 2008 assassination of the group's top military commander, Imad Mughniyeh, in a car bomb blast in the Syrian capital of Damascus.
Hezbollah and its primary patron, Iran, have blamed Israel for Mughniyeh's killing. Israel has denied involvement.
Nasrallah repeated his threats to Israel that Hezbollah will avenge Mughniyeh's assassination.
"The decision is still ours and, God willing, it will be carried out. I tell Zionist leaders and generals to watch out for your heads wherever you go in the world and whenever you go," he said. "Imad Mughniyeh's blood will not be wasted."
The Hezbollah leader was repeatedly interrupted by hundreds of supporters who waved their fists while chanting "at your service, Nasrallah."
On Tuesday, Israeli officials said the Jewish state temporarily closed at least four diplomatic missions abroad in response to threats against Israeli targets overseas.
The threats appeared to be tied to the anniversary of Mughniyeh's death.
Also Wednesday, a Hezbollah cell commander who escaped from an Egyptian prison during that country's recent uprising appeared at the Hezbollah rally.
Mohammed Youssef Mansour, better known as Sami Chehab, held up a Hezbollah flag and raised his hands in a V-for-victory sign Wednesday.
The Shiite militant group says that Mansour was among the thousands of prisoners across Egypt who are believed to have escaped or been set free shortly after the revolt against longtime President Hosni Mubarak erupted Jan. 25. This was his first public appearance.
Mansour was convicted in 2010 along with 25 others of spying for Hezbollah and plotting attacks in Egypt.