Beirut/Tel Aviv, July 13 (DPA) Israel Thursday launched the heaviest air strikes on Lebanon in 24 years while the militant Hezbollah movement fired a "unprecedented" barrage of rockets at northern Israeli towns and villages, prompting fears of another Middle East war.

More than 40 Lebanese civilians were killed and dozens wounded, as Israeli jets fired missiles at more than 170 targets in southern Lebanon by the late Thursday afternoon since the abduction of two Israeli soldiers and the killing of eight others by Hezbollah Wednesday.

Hezbollah retaliated for the Israeli strikes by firing more than 80 rockets at Israel, killing two people and wounding at least 90.

For the first time, the Lebanese guerrilla group fired missiles with longer ranges than before, some of them landing some 20 to 25 km from the border and reaching as far south as the Israeli city of Safed.

Israelis throughout the north of the country were ordered into bomb shelters and many residents of the coastal resort Nahariya, the hardest hit, were seen leaving the town.

Israel's highest-profile target in its attacks was Beirut International Airport, two of whose runways were struck by at least four missiles.

The strike caused no injuries, but sent black clouds of smoke to drift over the capital's southern outskirts, forcing all incoming flights to be diverted to Cyprus and elsewhere and leaving thousands of passengers stranded. Four large craters could be seen on the airport tarmac.

The Israeli army said the airport was targeted because the Lebanese government allowed Hezbollah unhindered use of it for the transportation of weapons of its armed wing.

A Hezbollah television station in southern Beirut was also targeted and in the afternoon Israel struck at a Lebanese Air Force base in east Lebanon, firing two missiles at one of the runways.

A senior army officer called the Israeli aerial offensive in Lebanon the widest since the 1982 Israel-Lebanon war. An army spokesman also spoke of an "unprecedented attack" by Hezbollah in terms of the number of Israeli villages hit and the depth of the missile strikes.

Israel clamped an "air, maritime and land blockade" on Lebanon, Lebanese military sources said, with Israeli warships entering Lebanese waters to enforce the blockade from the sea.

The Israeli Army only confirmed it imposed a blockade from the sea, saying the aim was to prevent the transfer of militants and the transportation of weapons to Hezbollah.

Israeli Prime Minister Ehud Olmert's security cabinet approved "Operation Appropriate Wage" overnight, hours after the two soldiers were snatched by Hezbollah fighters as they were on patrol along the border.

Its aim was to force Hezbollah to withdraw from the Israel-Lebanon border, Israeli media reported.

Defence Minister Amir Peretz said Israel would not relent until it received guarantees that the Lebanese army would replace Hezbollah in southern Lebanon.

"We will no longer allow Hezbollah's forces to sit on the border with Israel," he told reporters at his Tel Aviv office.

After Israel's May 200 withdrawal from a self-proclaimed "security zone" in southern Lebanon, the United Nations called for the disarmament of Hezbollah and for the Lebanese government to assert its authority and sovereignty over south Lebanon, which has been a stronghold of the Islamic fundamentalist militia since it was founded in the 1980s.

Israel has said it holds the Lebanese government, of which Hezbollah forms part, responsible for the soldiers' abductions which Olmert denounced as an "act of war" by Lebanon against Israel.

Speaking hours after the abduction of the two soldiers in northern Israel, Hezbollah chief Sheikh Hassan Nasrallah demanded a prisoner swap through indirect negotiations.

Hezbollah threatened to bomb the Israeli coastal city of Haifa if Israel attacked Beirut or its southern suburbs, considered a Hezbollah hotbed where many of the movement's leaders reside.