Mexico City, Muharram 01, 1439, September 21, 2017, SPA -- Mexico's disaster services enlisted firefighters, soldiers, police and volunteers to dig Wednesday for people trapped in collapsed buildings after a violent earthquake shook the country, killing more than 220 people, according to dpa. More than 40 buildings collapsed in Mexico City, including an elementary school where 21 schoolchildren and four adults were killed. Equipped with breathing masks, bicycle helmets, pickaxes and shovels, hundreds of volunteers helped in the rescue work in Mexico City. Using torches, they searched for the survivors in heaps of concrete left from the collapsed buildings. The earthquake seriously damaged about 500 other buildings in the Mexican capital, leaving many of them uninhabitable. The 7.1-magnitude tremor that struck on Tuesday afternoon occurred on the anniversary of a devastating earthquake that killed more than 10,000 people in 1985. People in Mexico City had just completed an annual earthquake drill two hours before the latest quake struck. Luis Felipe Puente, head of the civil protection service, said 225 bodies had been recovered. President Enrique Pena Nieto declared three days of national mourning in honour of the victims. He also urged the people of Mexico to remain united in the face of the challenge, with the death toll expected to rise. "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. Mexico City mayor Miguel Angel Mancera said there was a lack of experts who can inspect buildings, and the city is relying on about 200 engineering and architecture students and faculty at the University of Mexico (UNAM) to make up for the shortfall . "Many people have not been able to return home after cracks appeared in structures," Mancera told TV station Televisa. In addition to Mexico City, two states to the south of the capital, Morelos and Puebla, were badly affected. The epicentre of the quake was about 130 kilometres south of the metropolis near Axochiapan. The town of Atzala in the state of Puebla reported at least 11 deaths. The earthquake caused the roof and the dome of a church there to fall in during a baptism. The number of injured people across the country is estimated at 700, including 400 seriously. With several hospitals damaged, injured people were treated in the open air. The energy company CFE said 3.8 million people were temporarily without electricity, and the telephone network in Mexico City was erratic. The Education Ministry said 209 schools have been closed, 15 of them with severe damage. School has been cancelled for about 14 million schoolchildren for the time being. "The safety of children, young people and teachers is a priority," said Education Minister Aurelio Nuno. A distressing scene was unfolding at an elementary school where 25 bodies had been recovered and at least two children and one adult were still missing, Nuno said Wednesday morning. "We hear voices; some are still alive," said Jose Luis Vergara, a spokesman for the navy, which is also participated in the rescue effort. Pena Nieto visited the school in the south of the capital during the night. An earlier report said as many as 37 had died at the school, but authorities said the number of bodies recovered was 25, including 21 children. A number of schoolchildren were rescued. --SPA 03:44 LOCAL TIME 00:44 GMT www.spa.gov.sa/w492923