Israel has offered to halt air strikes in southern Lebanon for 48 hours to allow civilians to leave, said an Israeli foreign ministry official.
The announcement came hours after at least 57 people died in an Israeli air strike on Sunday on the southern Lebanese village of Qana.
The official said that despite the announced cessation, Israel would continue to attack any Hezbollah target actively engaged in attacking Israel. The Lebanese Shia militia has fired rockets daily into northern Israel since hostilities broke out on July 12.
The concession was made late Sunday after meetings between US Secretary of State Condoleezza Rice and Israeli officials.
"Israel has agreed to a 48-hour suspension of aerial activity in south Lebanon while it investigates today's tragic incident in Qana," US State Department spokesman Adam Ereli said in a statement issued from Jerusalem. "Israel has, of course, reserved the right to take action against targets preparing attacks against it."
Ereli said that the 48-hour window would include a 24-hour period of "safe passage for all residents of south Lebanon who wish to leave."
"Humanitarian convoys remain in effect," he said. "We expect that Israel will implement these decisions so as to significantly speed and improve the flow of humanitarian aid. The US welcomes this decision and hopes that it will help to relieve the suffering of the children and families of southern Lebanon."
Over 500 Lebanese, largely civilians, have been confirmed dead in Israeli air raids or by artillery and naval shelling. More than 1,200 Lebanese have been wounded.
Some 18 Israeli civilians have been killed by the close to 1,600 missiles Hezbollah has launched at Israel, and 33 soldiers have been killed in the fighting. Hundreds of Israelis have been wounded.
Israel's leaders have said that their aims in the fighting include destroying Hezbollah's ability to attack across the Israeli border and the return of the two abducted Israeli soldiers.