The toll from the powerful magnitude-7.1 earthquake that rocked Mexico earlier this week has risen to 292, the national emergency management chief has said.National Civil Protection Coordinator Luis Felipe Puente said in his latest preliminary report on fatalities on Friday that the number killed in Mexico City from Tuesday's powerful temblor had increased from 148 to 154, Efe news reported.Dozens of other people perished in nearby states, with 73 dead in Morelos, 45 in Puebla, 13 in Mexico state, six in Guerrero and one in Oaxaca.The number of missing has fallen from 200 in the initial count to 42 people who may still be trapped under the rubble of collapsed structures, Puente said.The Civil Protection chief reiterated Friday afternoon -- 72 hours after the quake struck -- that the search for survivors would continue until rescuers were certain that no one was still alive amid the wreckage.He also sought to allay fears that heavy machinery would be brought in to remove rubble at sites where people might still be trapped, telling people to call the 911 emergency number or an information hotline to inform authorities of such actions."We'll stop it if that's the case," Puente said.Teams from Chile, Colombia, Spain, Israel and Japan and other countries have arrived in Mexico to assist with the search for survivors.In an interview with a local radio station, Government Secretary Miguel Angel Osorio said that once the emergency phase had ended authorities would conduct a "house-by-house" census to determine the full extent of the earthquake damage.