Mexican President Enrique Nieto on Wednesday declared three days of national mourning in the wake of a 7.1-magnitude earthquake which has left over 200 people dead.
Nieto made the announcement on Twitter, saying the days of mourning were in honour of the victims.
“Mexico shares in your grief,” the president said.
In an earlier statement, he urged the people of Mexico to remain united in the face of the challenge.
“This earthquake is a hard and very painful test for our country, but we Mexicans have learned to respond with commitment and a spirit of solidarity,” he said.
The magnitude 7.1 quake, which killed at least 94 people in the capital alone, struck 32 years to the day after a 1985 earthquake that killed thousands.
Mexico is also still reeling from a powerful tremor that killed nearly 100 people in the south of the country less than two weeks ago.
As rescue efforts continued at a school, a facility for children aged 3 to 14, emergency crews, volunteers and bystanders toiled elsewhere using dogs, cameras and heat-seeking equipment to detect survivors.
Reinforcements also began to arrive from countries, including Panama, Israel and Chile, local media reported.
Hundreds of neighbours and emergency workers spent the night pulling rubble from the ruins of the school with their bare hands under the glare of floodlights.
Three survivors were found at around midnight as volunteer rescue teams known as “moles” crawled deep under the rubble.
The earthquake toppled dozens of buildings, tore gas mains and sparked fires across the city and other towns in central Mexico.
Even wealthier parts of the capital, including the Condesa and Roma neighbourhoods, were badly damaged as older buildings buckled.
Because bedrock is uneven in a city built on a drained lake bed, some districts weather quakes better than others.
Meanwhile, U.S. President Donald Trump has shown his support, saying in a tweet on Tuesday: “God bless the people of Mexico City. We are with you and will be there for you.”
Trump and Nieto spoke at length on Wednesday, according to the White House.