The plans to deploy troops have gathered pace as a fragile ceasefire held and thousands of displaced Lebanese jammed bombed-out roads in the hope of returning home.
"We would like to see 3,000 to 3,500 troops within 10 days to two weeks," said Hedi Annabi, the UN assistant secretary-general for peacekeeping operations.
"That would be ideal to help consolidate the cessation of hostilities and start the process of withdrawal and deployment of the Lebanese forces as foreseen in the (UN) resolution."
At the same time, a Lebanese army official said 15,000 troops would start deploying in the next few days as Israeli forces withdraw, fulfilling a key demand of the UN resolution on ending the month-long conflict between Israel and Hezbollah.
"I hope we can deploy the first reinforcements very quickly," the head of UN peacekeeping forces, Jean-Marie Guehenno, told French radio. "I would be happy if we saw the first elements arriving within 10 days. That would be a very good sign."
Israeli army chief Dan Halutz said it would take "one week to 10 days" for his troops to transfer control of south Lebanon to the Lebanese army.
Volatile situation
But in an indication of the still volatile situation on the ground, the Israeli army said it killed at least three Hezbollah fighters and that a dozen rockets targeted army positions in the region but that soldiers chose not to return fire.
Israel also warned displaced southern Lebanese not to attempt returning home until the Lebanese army had deployed in the region, saying conditions were "dangerous."
UN Security Council Resolution 1701, unanimously adopted on Friday to end a conflict that has killed 1,300 people and devastated Lebanon, mandates that the multinational UN Interim Force in Lebanon (UNIFIL) will swell from its current level of 1,990 troops to 15,000.
No precise timetable has been set for the deployment of the force, which will likely include contingents from France, Italy, Malaysia, Belgium and another half-dozen countries.
But UN Secretary General Kofi Annan said on Monday that he had not yet received firm commitments from countries who have said they may contribute troops to the international contingent.
Despite accepting the ceasefire resolution, Hezbollah said it would keep on fighting until the last Israeli soldier leaves Lebanon, while Israeli Prime Minister Ehud Olmert said vowed to hunt down the group's leaders.
UN humanitarian relief chief Jan Egeland warned in an interview with a Russian newspaper that the humanitarian situation "is on the verge of catastrophe".
"(Israelis) should think hard before they bomb civilian objects," Mr Egeland said, and also criticised Hezbollah, saying that its fighters had hidden or carried out strikes against Israel from among the civilian population.
Hezbollah death toll
Israeli Deputy Prime Minister Shimon Peres said Israel's five-week assault on Hezbollah left nearly half the Shiite militia's estimated fighting force of 2,500 men dead or wounded.
"We estimate Hezbollah lost something like 600 fighters (and) one can imagine 600 others wounded, amounting to 1,000 to 1,200 out of a force of 2,500," he said.
There was no way of independently verifying Mr Peres's assertion.
UN employee killed
The UN agency that looks after Palestinian refugees has condemned Israel's "absurd and tragic" killing of one of its employees in southern Lebanon minutes before a ceasefire came into effect on Monday.
The UN Relief and Works Agency said an Israeli air strike on the Ein el-Helweh Palestinian refugee camp 80 minutes before the ceasefire killed a 48-year-old male employee who was married with three children.
"UNRWA strongly condemns the death of Mr Saghir ... the fact that he was killed when hostilities were going to end makes his death particularly absurd and tragic," it said in a statement.
It said one of the missiles fired targeted a Palestinian faction in the camp, Lebanon's largest and home to 47,000 Palestinians.
Palestinian activists hit
Palestinian security officials quoted by AFP said two Palestinian activists were hit by Israeli gunfire in the southern Gaza Strip yesterday.
The men, said to be members of the Al-Qods Brigades - the armed branch of the radical Islamic Jihad movement - were hit in an area east of the town of Khan Younes.
It was not immediately known if they were wounded or dead.
An Israeli military official said soldiers had opened fire after spotting two men crawling towards the barrier which separates Israel and the Gaza Strip at the Kissufim border crossing.
Search for reporters
Meanwhile Palestinian security services have stepped up the hunt for two foreign journalists from the US television channel Fox News after their abduction by armed men in Gaza Strip.
"We have begun an investigation to determine who kidnapped the two journalists in Gaza, and we have begun a search to find them as soon as possible," a spokesman for the Palestinian interior ministry told AFP.
US reporter Steve Centanni and freelance cameraman Olaf Wiig, from New Zealand, were snatched by gunmen who intercepted their car in Gaza City late Monday.
"Two of our colleagues were abducted yesterday in Gaza," a spokeswoman for Fox in Jerusalem told AFP. "There are some negotiations. We hope they will be released soon."
Fox said that the pair had been reporting from the region for several weeks.