Israel has told the U.N. Security Council it is opening a two-way humanitarian corridor into and out of Lebanon. The Israeli pledge came in response to increasingly sharp international criticism for its military offensive in Lebanon.

As an Israeli ground assault into southern Lebanon appeared imminent Friday, U.N. emergency aid chief Jan Egeland told the Security Council that Israel's destruction of Lebanese roads and bridges had worsened an already grave humanitarian crisis. He said fuel and other essential items are in short supply.

"As a result of the targeting of petrol stations and fuel storage facilities, it is estimated that Beirut has only days of fuel supplies remaining," he said. "Access problems are severely hampering humanitarian action. It is either too unsafe or physically impossible due to destruction, to move supplies into or around large parts of the country."

After he spoke, Egeland flew to the region for a first-hand assessment of the humanitarian challenge.

In the face of mounting diplomatic pressure, Israel's U.N. Ambassador Dan Gillerman told the Council his country is opening a humanitarian corridor.

"I have just received official confirmation from Israel that further to the corridor allowing evacuation from Lebanon, a two-way in-and-out humanitarian corridor to meet needs of those affected on the Lebanese side has been established," he said.

Gillerman added that both sea and land corridors could open as early as Saturday.

Friday's session heard dozens of urgent pleas for international intervention to stop the Israeli military offensive.

Lebanese special envoy Nouhad Mahmoud charged that Israeli bombs and artillery had turned his country into a disaster zone. He ridiculed Israel's humanitarian corridor pledge.

"We just heard the distinguished representative of Israel informing us that they have accepted a safe corridor for victims of the aggression carried out by his country as if we are supposed to salute and pay tribute to the compassionate feelings they have," he said.

Israel's Ambassador Gillerman sat through much of the day-long session, listening as speaker after speaker condemned his government's offensive. But when it was Syria's turn to speak, Gillerman walked out.

Syria's Ambassador Bashar al-Jaafari charged that U.S. backing for Israel was the cause of instability in the Middle East.

"Instability in the region is caused by continued occupation by Israel of Arab territories and the impunity enjoyed by Israel, granted to it by some influential powers to act as if it is above the law at the expense of our legitimate right in Palestine, Lebanon and the Golan," he said.

A three-member U.N. team that just returned from Middle Eastern capitals gave a grim assessment of the outlook for a quick end to the hostilities. Team leader Vijay Nambiar said it is difficult to imagine a sustainable ceasefire in the absence of a political framework.

"From the mission's consultation, it became clear that there are serious obstacles to the achievement of a comprehensive ceasefire in the immediate future," said Nambiar.

In a sign of the seriousness of the current crisis, Secretary-General Kofi Annan was uncharacteristically silent Friday. In an address to the Council a day earlier, he called for an immediate end to hostilities, and overnight he met privately with U.S. Secretary of State Condoleezza Rice.

He attended the opening of Friday's meeting, but did not speak.

Friday's seven-hour Council meeting adjourned without any action.