Early reports indicated three to five people died and more than 60 were injured in the blast Thursday night, said Jose Antonio Marquez, a spokesman for Veracruz state. A federal highway policeman had earlier said 15 died, though several Red Cross officials said the reports were unconfirmed.
The explosion apparently ripped through an area of small roadside restaurants called Balastrera, about 115 miles southeast of Mexico City.
Many truckers stop there to sleep, said Alejandro Martinez of the Red Cross in nearby Orizaba.
The federal oil company, Petroleos Mexicanos, said in a statement that initial reports indicated a landslide caused by pounding rain broke a 24-inch gas line, setting off an explosion at about 7:50 p.m.
Flooding was reported in at least seven neighborhoods in the nearby town of Nogales, and officials there told the Formato 21 radio station in Mexico City that 80 to 100 people had to be evacuated to the city hall.
Troops were aiding police, and the Red Cross sent ambulances from cities as far as 25 miles away.
The flooding and mountainous terrain that blocked radio signals complicated efforts to determine the scope of the explosion, which forced closure of the main expressway between Mexico City and the Gulf coast for at least two hours.
