Israeli forces have been gathering near the border with Lebanon
Israel has massed soldiers and tanks on the border with Lebanon and called up thousands of reserve troops, in a possible prelude to a ground offensive.
Planes dropped leaflets on southern Lebanon warning any civilians to leave.
Israeli soldiers are already fighting Hezbollah inside Lebanon, but the army chief of staff said any incursion into the country would be limited in scope.
The US secretary of state is to travel to the Middle East on Sunday in an attempt to resolve the crisis.
Condoleezza Rice said she was seeking an "endurable peace" - but not an immediate ceasefire that would return the region to the pre-conflict era.
The crisis was triggered by the capture of two Israeli soldiers by Hezbollah militants on 12 July.
The tenth day of fighting saw fresh Israeli air raids and shelling and Hezbollah rocket-fire on Israel's city of Haifa.
In other developments:
Images from Beirut as the scale of destruction begins to emerge
Italy will host an international conference on the crisis next Wednesday
Israel's military chief said the country's forces had killed nearly 100 Hezbollah fighters in Lebanon
Top UK aid agencies united to call for a ceasefire
The evacuation of foreign nationals from Lebanon continued.
Bulldozer burials
The call-up has widened speculation the Israeli army is preparing for a major ground offensive, after days of what they call "restricted pinpoint attacks" into southern Lebanon in search of Hezbollah weapons and facilities.
Correspondents in Jerusalem say it is understood the Israeli reservists being called up could fill in for troops in the West Bank and Gaza, releasing other soldiers to go up to the northern front.
Hundreds of armoured vehicles are backed up south of the Lebanese border.
However, Israeli army chief of staff Dan Halutz said they would "conduct limited ground operations as much as needed" to "harm the terror that harms us".
Senior Lebanese officials said the country's army would go into battle if Israel invaded Lebanon.
The call-up came as residents of southern Lebanon continued to flee the area, and in the city of Tyre a bulldozer was used to bury 80 people killed in the region.
The regional capital of south Lebanon, Sidon, says about 28,000 internally displaced people have already crammed into the small sea port - and it is becoming dangerously overcrowded.
Sidon's mayor has warned that food, medicines, water and accommodation are running out.
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An illustrated developmental history of the American military chemical and biological protective respirator for use against war agents, this work provides photographs of actual respirator specimens and several useful appendices, in addition to its en
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