Mexico's civil protection coordinator, Luis Felipe Puente said that the search and rescue operations for survivors from Tuesday's quake in Mexico City could possibly last "for at least two more weeks".
There has been anger in Mexico after it became apparent that a young girl who was believed to be trapped under the rubble of a collapsed school never actually existed.
Saturday's natural disaster destroyed a highway bridge as well as homes already damaged by previous quakes.
At least 273 people were killed - a toll that rose slightly from Tuesday to Wednesday - and scores more are injured across central Mexico.
The death toll in this week's massive quake that toppled buildings in Mexico City and elsewhere rose to at least 295, the country's national civil defense coordinator said, as rescuers continued to look for those trapped in the rubble.
The earlier September 7 quake killed almost 100, mostly in Oaxaca and neighboring Chiapas state. Many tourists were killed in the quake and officials today recovered bodies of eight foreigners that includes citizens of Taiwan, Korea, Spain and Argentina.
Authorities have registered more than 4,000 aftershocks from the September 7 quake, but Saturday's appeared to be the strongest.More news: Manchester United revenue likely to repeat
On the third day of the rescue effort, hopes were dwindling that victims in other parts of the city or surrounding states might be saved.
The first tremors were reported by the National Seismological Service (SSN) in Oaxaca at 2:12 am, whose epicenter was 50 kilometers south of Salina Cruz, with a magnitude of 4.1.
Frida, a celebrity on social media, has caught the attention of Mexican President Enrique Pena Nieto, who recently tweeted this video on her.
"We want to be superheroes so that our country doesn't suffer", she said at a site where volunteers brought a wheelbarrow filled with candy for the rescue teams.
One of the most seismically active countries in the word, Mexico has been hit hard by earthquakes this month.
"I was frightened because I thought, not again!"
The highest number of fatalities, that of 137, was in Mexico City. Senior officials said there could be 20,000 badly damaged homes in the states of Morelos and Puebla.