"We warn you not to head to the southern regions before the deployment of the forces that are supposed to safeguard your security," said leaflets dropped by Israeli aircraft in south Lebanon on Tuesday.
Despite the warning, thousands of vehicles jammed the bombed-out coastal highway linking Beirut to the south from the early hours of Tuesday as thousands of displaced people headed home.
The United Nations refugee agency warned that returning civilians were at danger from unexploded bombs and shells.
"People need to be aware the dangers are very high," said Astrid van Genderen Stort, spokeswoman for the UN refugee agency UNHCR. She said there had been at least eight incidents involving unexploded ordnance, but had no word on casualties.
Israeli forces have pulled back from the town of Marjayoun in southern Lebanon and nearby areas, Lebanese security officials said on Tuesday.
By Tuesday, there were no Israeli soldiers or tanks in Marjayoun, security officials said, while Israeli troops were also reported to be pulling out of the towns of Bourj Al-Mulouk and El-Ghandourieh.
Israeli military officials have said they hope to complete their withdrawal of forces by next week, marking an end to five weeks of fighting which has left scores dead on both sides.
Earlier on Tuesday, a dozen rockets were fired at positions held by Israeli soldiers in south Lebanon despite a United Nations-brokered truce which came into effect on Monday morning, however the Israeli military said it did not return fire.
The rocket attacks caused neither casualties nor damage, the spokesman said.
Despite accepting the UN truce, Hezbollah has vowed to keep on fighting until the last Israeli soldier leaves Lebanon, while Ehud Olmert, the Israeli prime minister, has promised to hunt down the group's leaders.
Olmert on Monday took full responsibility as opposition politicians demanded a commission of inquiry into the conduct of the battle with Hezbollah.
In a nationally televised speech to parliament hours after a ceasefire took effect in Lebanon, Olmert painted the war and the UN resolution that ended the fighting as an important victory for Israel that changed the strategic balance in the region and badly weakened Hezbollah.
Israeli soldiers shot three Hezbollah fighters in southern Lebanon on Tuesday, the Israeli army said. A spokeswoman said she did not know if any of them had been killed.
The UN peacekeeping force in south Lebanon said that it had not observed any breaches of the truce.
Donors to meet
Meanwhile, Sweden invited 60 countries and aid agencies to a donors' conference aimed at helping Lebanon rebuild homes, roads and lives shattered by weeks of fighting between Israel and Hezbollah fighters.
Big donor nations such as the United States, France, Britain, Germany, Norway and Japan as well as the Gulf states were among those invited to the August 31 conference in Stockholm, Carin Jamtin, the Swedish aid minister, said on Monday.
Lebanon's infrastructure and
buildings have taken a battering
She declined to place a figure on how much aid was needed, saying that was up to Lebanon to determine.
Also on Monday, the French general leading the UN peacekeeping force in Lebanon said he wanted reinforcements quickly, warning that even one "stray act" could unravel a diplomatic effort to halt the fighting between Israel and Hezbollah.
Alain Pellegrini said the UN resolution could give unprecedented new strength to the 28-year-old UNIFIL force - which has often been criticised as ineffective in the past.
The UN plan calls for a joint Lebanese-international force to move south of the Litani River, about 30km from the Israeli border, and act as a buffer between Israel and Hezbollah fighters.