A woman in Curepto, Chile, walks past buildings destroyed in the earthquake. (Cristobal Saavedra/Reuters)Chile has revised its estimate of the number of people killed in the Feb. 27 earthquake down to 279, backing away from earlier estimates that put the death toll at 802.

The government said that it has been difficult to determine how many people died in the earthquake because of problems with the communication system and confusion surrounding missing people.

The death toll is expected to change as officials identify bodies and make contact with people who were missing.

Meanwhile, residents in Concepcion were forced out of their homes early Friday morning when a series of aftershocks — including one 6.3-magnitude quake — rumbled through the southern city, sending people running from buildings.

Chilean firemen search through a destroyed apartment building in Concepcion Wednesday. (Ruiz Caballero/Reuters)Concepcion, roughly 500 kilometres south of the capital Santiago, was hit hard by Saturday’s earthquake. Many buildings — including a 15-storey apartment tower — were badly damaged in the earthquake, and military personnel had to be sent to the city to control looting after the quake.

The aftershocks damaged several buildings, including the local hospital.

"They sent us all home," said Aaron Valenzuela, 47, who hobbled through the street because four toes had been amputated due to an injury he suffered in Saturday's big quake.

Dr. Patricia Correa, who was overseeing the hospital's emergency ward, said her part of the five-storey building "is on the point of collapsing. The walls cracked."

Will avoid interrupting aid

Outgoing President Michelle Bachelet, meanwhile, met with her successor, Sebastian Pinera, and they promised to try to avoid letting the March 11 handover of power interrupt aid efforts.

The earthquake caused an estimated $30 billion US in damage, and Bachelet said the country would likely need access to international credit to rebuild the country's infrastructure.

UN Secretary-General Ban Ki-moon arrived in Santiago Friday promising support for Chile.

"The Chilean government is asking for international aid, and we will give it," he said.

Amir Dossal, executive director of the UN Office for Partnerships, said private donations have begun to arrive, among them $1 million from Wal-Mart and $500,000 from Hewlett Packard.

On Thursday, Bachelet said the reconstruction effort would likely take between three and four years to complete.

"The new government will have an immense challenge," Bachelet said.

She has declared a three-day period of national mourning starting on Sunday for victims of the quake.

With files from The Associated Press