MEXICO CITY -- At least six U.S. airlines cancelled 47 flights into and out of the Mexico City and Toluca airports Thursday after the Popocatepetl volcano spewed ash, steam and glowing rocks, airport officials said.
Mexico City airport spokesman Jorge Gomez said U.S. Airways, Delta, United, American and Alaska Airlines cancelled the flights as a precaution. But he said the airport otherwise continues to operate normally and that by Thursday afternoon no ash had reached the area, about 40 miles (70 kilometres) northwest from the volcano.
Gomez said that among the routes affected by the cancellations were flights to Houston, Dallas, Denver, Phoenix, Chicago and Los Angeles.
At nearby Toluca airport, Spirit Airlines cancelled flights from Dallas and Fort Lauderdale, said spokesman Alejandro Munoz.
The airport, about 35 miles (60 kilometres) from Mexico City, also continued to operate normally, Munoz said.
While there was no volcanic ash falling near the Mexico City airport, residents in the capital's southern neighbourhoods reported seeing a light coating on their cars and homes.
Mexico City civil protection secretary Fausto Lugo said the main risk for the metropolis is people not knowing how to handle ash and how to protect potable water from getting contaminated.
"If there is an eruption, we wouldn't evacuate Mexico City," Lugo said. "For us the main risk is the handling of volcanic ashes."
Authorities registered several tremors Thursday at the 17,886-foot (5,450-meter) volcano, which has been spraying a fountain of hot rock and ash for the last 24 hours.
Federal civil protection authorities established a 7-mile (12-kilometre) safety radius around the Popocatepetl, which means no one can enter that area. They also are ensuring that no cars transit through the Paseo de Cortes, a mountain pass between the Popocatepetl and Iztaccihuatl volcanoes.
An iconic backdrop to Mexico City's skyline on clear days, Popocatepetl sits roughly halfway between Mexico City and the city of Puebla.