Constitucion: UN Secretary General Ban Ki-moon was to visit this earthquake-struck Chilean city on Saturday to assess its needs as new fears spread among Chileans following three strong aftershocks.
The Navy meanwhile sacked the head of the Oceanography Service, saying he had failed to provide a clear warning of the deadly tsunami that followed Saturday`s 8.8-quake, as criticism grew of the official disaster response.
A first 6.2-magnitude aftershock jolted people awake at 6:20 am (0920 GMT), on Friday just six days after the 8.8-magnitude quake which, along with the tsunami, left more than 800 people dead and some two million homeless.
That was followed by a 6.8-magnitude tremor -- one of the strongest of more than 200 to rattle Chile since the weekend -- and another measuring 6.6.
Some damaged buildings in Concepcion, the country`s second city and worst affected by the big quake, collapsed, but the national emergency services said the aftershocks caused no injuries or serious damage.
Oceanography chief Mariano Rojas was removed from his post on Friday, and the head of the Navy opened an investigation into their response to the catastrophe, an official statement said.
Military officials have admitted making a mistake following the quake.
They said had transmitted "very unclear information" to President Michelle Bachelet on whether to lift or maintain a tsunami alert, as giant waves began crashing into the Pacific coast.
The UN secretary general arrived in the capital Santiago on Friday to assess the damage and meet with Bachelet and president-elect Sebastian Pinera.
He was due to travel on Saturday to Concepcion, and was expected to stop in Talcahuano, a port hit by the tsunami.