Israel is continuing its bombardment of Lebanon, with dozens of air strikes leaving at least five people dead.
Israeli aims are shifting as it meets greater than expected resistance
Strikes hit the eastern Bekaa Valley and villages in the south, and some ground clashes are reported.
About 420 Lebanese, mainly civilians, are confirmed to have died since the conflict began more than two weeks ago.
Some 51 Israelis - 18 of them civilians - have been killed, mostly by rockets fired over the border by the Lebanese guerrilla group Hezbollah.
The Israeli assault began after Hezbollah captured two Israeli soldiers in a cross-border raid on 12 July.
UK Prime Minister Tony Blair is flying to Washington for talks with US President George W Bush.
The meeting comes amid growing pressure for the UK and US to join calls for an immediate ceasefire between Israel and Hezbollah.
At talks in Rome on Wednesday, the US, UK and regional powers called for a ceasefire with "utmost urgency", but stopped short of calling for an immediate truce.
But on Friday a spokesman for the US Department of State dismissed as "outrageous" a suggestion by Israel that it had been given a green light to continue its campaign.
Israel jets pounded targets in Lebanon as its campaign, which has seen hundreds of thousands of civilians displaced, entered its 17th day.
There were multiple strikes on the Bekaa Valley to the east, on villages around the coastal city of Tyre, and roads in the south-east.
In Kfar Joz, close to the southern market town of Natabiyeh, a Jordanian man was killed by shrapnel from an Israeli attack.
A Lebanese couple there died when their bomb shelter collapsed on top of them, and at least three children were wounded.
Sporadic clashes were also reported in Bint Jbeil, where Israel suffered its worst single losses on Wednesday, with nine soldiers killed.
The BBC's Jim Muir, in the southern coastal city of Tyre, encountered a large convoy of refugees who fled the bombardment in the south under the protection of the Red Cross.
Some of the villagers, who had been trapped in their homes for more than two weeks, were hysterical, our correspondent reports. They spoke of horrendous conditions as the shells rained down, with food and water running out as they crouched in their homes in terror.
Refugees arriving in Tyre spoke of desperate conditions
Though the confirmed Lebanese death toll is about 420, the health minister estimated some 600 people may have died, with scores of bodies undiscovered under rubble.
In Israel, there is growing concern that Hezbollah is still firing large numbers of missiles into northern Israel.
Few in Israel still speak of being able to neutralise Hezbollah, our correspondent in Jerusalem Katya Adler says.
Instead Israel speaks of trying to establish a "secure zone" empty of Hezbollah fighters north of the border with Israel.
The Israeli government's announcement that it is calling up three divisions of reservists - said to number between 15,000 to 40,000 - suggests it is preparing for the possibility of a protracted war, our correspondent says.
In other developments, high-level representatives of Syria and Iran were due to meet in Damascus to discuss the crisis.
LEBANON TWO WEEKS ON
Three airports bombed
62 bridges destroyed
Three dams and ports hit
5,000 homes damaged
Syrian cabinet minister Bouthaina Shaaban said it was no surprise the Rome talks had no real results given the absence of Syria and Iran.
Both countries are accused by the US and Israel of arming Hezbollah.
The minister said while Arab lands were occupied by Israel, "violence is going to erupt".
She repeated a Syrian offer of dialogue over the conflict, saying Syria was prepared to use its influence with Hezbollah on certain conditions: a ceasefire in Lebanon first, followed by an exchange of prisoners, and then full discussion of all Arab territory currently occupied by Israel.