Lebanese Prime Minister Fouad Siniora has made an impassioned plea for help in rebuilding his country following the recent conflict with Israel.
Thousands of homes were destroyed in the month-long conflict
Mr Siniora told delegates at an international donors' conference in Sweden Lebanon's recovery from its civil war had been "wiped out in days".
Organisers are hoping to raise $500m (£260m; 392m euros).
Meanwhile UN chief Kofi Annan has arrived in Syria on the latest leg of a regional tour to bolster the ceasefire.
Mr Annan was met at Damascus airport by Syrian Foreign Minister Walid al-Moallem.
The two men will hold formal talks later in the day and on Friday morning Mr Annan will meet President Bashar al-Assad.
Stopping off in Jordan on Thursday morning, Mr Annan reiterated his call for Israel to lift its air and sea blockade of Lebanon.
Israel imposed the blockade to stop arms reaching Hezbollah militants after fighting with the Lebanese group erupted on 12 July.
However, at the donors conference in Sweden, the head of the US aid agency USAid refused to call on Israel to lift the blockade.
Randall Tobias said the emphasis should be on implementing all the measures in the UN Security Council resolution which put an end to the fighting, including securing Lebanon's borders and stopping the transport of arms except to the Lebanese government.
DAMAGE TO LEBANON
Infrastructure 15,000 homes, 78 bridges and 630km of roads damaged
Agriculture Up to $185m of crops, 1m poultry, 25,000 goats and sheep lost
Economy 6% growth (forecast) set to plunge, unemployment up
The Israeli army says it has handed back control of one part of its border with Lebanon, near the Israeli town of Metulla, to the Lebanese authorities.
It is the first time since the ceasefire between Israel and Hezbollah that Israeli troops have withdrawn from any part of the border area.
The BBC's Jill McGivering in Jerusalem says that many will see this as a positive move which will help to build confidence during a time of difficult transition from conflict to a more durable peace.
Mr Annan has tried to press Israel to give a definite commitment on when it will withdraw all of its troops, but so far Israeli leaders have refused to agree to a specific plan.
Earlier, Israel came in for strong criticism from the UN over its use of cluster bombs during its Lebanon offensive.
Unexploded cluster bombs litter the ground in southern Lebanon
"I think those kinds of weapons should not be used in civilian and populated areas," Mr Annan said, urging Israel to give the UN maps of the areas that were bombed so civilians in those areas could be protected and the bombs disarmed.
At the donors' conference in Sweden, Mr Siniora told delegates the month-long conflict had plunged Lebanon's economy into a "deep recession".
"Lebanon, which only seven weeks ago was full of hope and promise, has been torn to shreds by destruction, displacement, dispossession, desolation and death," he said.
He said direct damage to Lebanon was "running into the billions of dollars", while losses to the economy would cost billions of dollars more.
Fifteen years of development since the end of Lebanon's 1975-1990 civil war had been "wiped out in a matter of days by Israel's deadly military machine", Mr Siniora said.
The Lebanese government has previously put the cost of damage at $3.6bn.
It says 15,000 homes were damaged in the conflict and has appealed for $75m for temporary housing and $30m to repair major roads and put up bridges.
It has also asked for funds to help clear landmines and unexploded cluster bombs, which are preventing farmers returning to their fields.
On Wednesday the UN's humanitarian chief condemned the "completely immoral" way Israel dropped thousands of cluster bombs on Lebanon even as a resolution appeared imminent.
Israel says the weapons it uses are not illegal.
Ministers from more than 60 countries are attending the donors' conference, as well as officials from the UN, the World Bank, the International Monetary Fund, and the Red Cross.
On Thursday the UK raised its contribution to £21.5m ($40.1m).
The European Union has already promised 42m euros (£28m) for Lebanon's short-term recovery.
But Swedish foreign ministry spokesman John Zanchi said organisers were hoping for much more.
"We are hoping the international community will step up," he said.
Before the conflict erupted, Lebanon had one of the more promising economies in the Middle East, with the government forecasting strong growth of 6% and paying off its debts.
Now it says output will plummet and it will run a deficit for the first time in several years. Unemployment is up sharply, and industry, agriculture, tourism and fishing were badly damaged.