At least 60 dead, hundreds injured in Mexico's strongest quake in 85 years

 At least 60 people died when the most powerful earthquake to hit Mexico in over eight decades tore through buildings and forced mass evacuations in the poor southern states of Oaxaca and Chiapas, triggering alerts as far away as Southeast Asia.

The 8.1 magnitude quake off the southern coast late Thursday was stronger than a devastating 1985 temblor that flattened swathes of Mexico City and killed thousands.

This time damage to the city was limited as the quake was deeper and farther away, but it still sent thousands of people scurrying from their homes onto the streets when the violent rumbling began that also shook Guatemala and El Salvador.

"It almost knocked me over," said Gildardo Arenas Rios, a 64-year-old security guard in Mexico City's Juarez neighbourhood, who was making his rounds when buildings started to tremble.

The Oaxacan town of Juchitan on Mexico's narrowest point bore the brunt of the disaster, with sections of the town hall, a hotel, a church, a bar and other buildings reduced to rubble.

"The situation is Juchitan is critical; this is the most terrible moment in its history," the local mayor, Gloria Sanchez, said a few hours before President Enrique Pena Nieto flew to the battered town to oversee rescue efforts.

Facades of shattered buildings, fallen tiles and broken glass from shop fronts and banks littered the pavements of Juchitan while heavily armed soldiers patrolled and stood guard at areas cordoned off due to the extent of the damage.

Startled residents stepped through the rubble of about 100 wrecked buildings, including houses, a flattened Volkswagen dealership and Juchitan's shattered town hall. Scores paced the terrain or sat outside warily, mindful of the frequent aftershocks.

"Look at what it did to my house," said Maria Magdalena Lopez, in tears outside its battered walls. "It was horrifying, it fell down."

Alma Rosa, sitting in vigil with a relative by the body of a loved one draped in a red shroud, said: "We went to buy a coffin, but there aren't any because there are so many bodies."

All the deaths were in three neighbouring states clustered near the epicentre that lay about 70 km (40 miles) off the coast.

In Oaxaca, 45 people died, many of them in Juchitan, while in Chiapas 12 and in Tabasco three people lost their lives, according to federal and state officials.

In Chiapas, home to many of Mexico's indigenous ethnic groups, thousands of people in coastal areas were evacuated as a precaution when the quake sparked tsunami warnings.

Waves rose as high as 2.3 feet (0.7 meter) in Mexico, the Pacific Tsunami Warning Center said, though that threat passed.

State oil company Pemex said it was checking its installations for damage and closed the Salina Cruz refinery in the same region as the epicentre as a precautionary measure. It began restarting the 330,000 barrel-per-day refinery on Friday afternoon.

WOKEN IN THE NIGHT

At least 250 people in Oaxaca were also injured, according to agriculture minister Jose Calzada.

Classes were suspended in much of central and southern Mexico on Friday to allow authorities to assess the impact. Dozens of schools were damaged, officials said.

People ran into the streets in Mexico City, one of the world's largest metropolises and home to more than 20 million, and alarms sounded after the quake struck just before midnight.

Scores stood outside in central neighbourhoods, some wrapped in blankets against the cool night air. Children were crying.

Liliana Villa, 35, who was in her apartment when the quake struck, fled in her nightclothes.

"It felt horrible, and I thought, 'This (building) is going to fall,'" she said.

The U.S. Geological Survey (USGS) said the quake's epicentre was 54 miles (87 km) southwest of the town of Pijijiapan at a depth of 43 miles (69 km).

John Bellini, a geophysicist at the USGS National Earthquake Information Center in Golden, Colorado, said Thursday's quake was the strongest in Mexico since an 8.1 temblor struck the western state of Jalisco in 1932.

Across the Pacific, the national disaster agency of the Philippines put the country's eastern seaboard on alert for possible tsunamis, although no evacuations were ordered.