"It is inconceivable that it has taken five days for two entire regiments, backed by artillery and the air force, to overcome, with heavy losses, resistance by a hundred Hezbollah fighters in Bint Jbeil," said military analyst Reuven Pedatzur.

The battle for the flashpoint Lebanese border town of Bint Jbeil, which left nine Israelis dead on Wednesday and has reportedly killed dozens of Shia militants, was continuing on Friday.

"The army high command led the government to believe that the battle would take just a few days," Pedatzur told AFP. "Either it was badly informed by military intelligence or else it misinterpreted its information."

Israel began its campaign in Lebanon with brash claims that it would quickly annihilate the Lebanese Shia militia, but after 17 days of relentless air strikes and cross-border incursions, it was settling for far more modest goals.

Now the main objectives are to weaken Hezbollah, push it back from the border, and stop it firing rockets into Israel, as well as retrieving the two soldiers abducted on the border on July 12. The capture of those soldiers sparked the conflict.

Israel has called up an additional 30,000 reserve troops to help achieve those aims.

The army itself admits that Hezbollah had some nasty surprises in store for Israel's soldiers.

Captain Doron Spielman said Hezbollah fighters have had ample time since Israel pulled out of south Lebanon in 2000 to prepare themselves for a new conflict, digging underground bunkers and stocking up on weapons Israel says are delivered from Iran.

"We're facing a real army that uses the Lebanese civilian population as a shield because it knows that we don't want to cause thousands of deaths by carpet bombing," the military spokesman told AFP.