The United Nations says four UN peacekeepers have been killed in an Israeli airstrike on a UN post in southern Lebanon.
UN Secretary-General Kofi Annan, speaking in Rome, called on Israel to investigate what he called the "apparently deliberate targeting" of the UN post.
A spokesman for the UN peacekeeping force in Lebanon UNIFIL says the airstrike was a direct hit on the UN post in the town of Khiam.
Meanwhile, Hezbollah leader Hassan Nasrallah said in a televised speech Tuesday that his guerrilla group will begin firing rockets into Israel beyond the northern port city of Haifa.
Hezbollah has fired scores of rockets into northern Israel since the fighting began two weeks ago. A barrage of rockets Tuesday injured at least 18 people in Haifa.
His comments came as fighting raged in southern Lebanon Tuesday for the second straight day. Israeli military officials say they took control of the Lebanese border town of Bint Jbail, a Hezbollah stronghold. They say at least 20 Hezbollah guerillas were killed.
The Israeli military also says a senior Hezbollah commander Abu Jafar was killed in a gunfight near the southern Lebanese border village of Maroun al-Ras.
To the north, Israeli forces pounded Beirut for the first time in nearly two days. Smoke hovered over Hezbollah strongholds in the city's southern districts.
Meanwhile, a senior Hezbollah official told the Associated Press the guerrilla group did not expect Israel to respond so strongly to the recent capture of two Israeli soldiers.
The official Mahmoud Komati says Hezbollah expected -quote - "the usual, limited" response from Israel.
Israel began its offensive against Hezbollah after guerrillas captured two Israeli soldiers. The violence has claimed the lives of more than 370 Lebanese, almost all civilians, and 37 Israelis. About 20 Israeli troops have died in the fighting.
Information for this report is provided by Reuters, AP and AFP.