Latest: Mexican earthquake death toll rises to at least 15 people

The US Geological Survey said the earthquake hit off southern Chiapas state near the Guatemalan border with a magnitude as 8.1 - equal in force to a 1985 quake that killed thousands and devastated large parts of Mexico City.

Hundreds of buildings collapsed or were damaged, power was cut to more than 1.8 million people and authorities closed schools in at least 11 states for safety checks.

The US Geological Survey recorded at least 20 aftershocks of magnitude 4.0 or greater within about five hours, and the president warned that a major aftershock as large as magnitude 7.2 could occur.

The USGS said the quake struck at 11.49pm on Thursday and its epicentre was 102 miles west of Tapachula in Chiapas. It had a depth of 43.3 miles.

The quake caused buildings to sway violently in Mexico's capital more than 650 miles away, and people still wearing nightclothes fled into the streets, gathering in frightened groups.

Chiapas governor Manuel Velasco said three people were killed in San Cristobal, including two women who died when a house and a wall collapsed. He called on people living near the coast to leave their houses as a protective measure.

"There is damage to hospitals that have lost energy," he said. "Homes, schools and hospitals have been damaged."

Tabasco governor Arturo Nunez said two children died in his Gulf coast state. One of them was killed when a wall collapsed, and the other was a baby who died in a children's hospital that lost electricity, cutting off the infant's ventilator.

The Pacific Tsunami Warning Centre said waves more than 3ft above the tide level were measured off Salina Cruz, Mexico. Smaller tsunami waves were observed on the coast or measured by ocean gauges in several other places.

The centre's forecast said Ecuador, El Salvador and Guatemala could see waves of 3ft. No threat was posed to Hawaii and the western and South Pacific.

Mexican authorities were evacuating some residents of coastal Tonala and Puerto Madero because of the warning.

The quake hit as emergency agencies were bracing for another crisis on the other side of the country. The US National Hurricane Centre said Hurricane Katia is likely to strike the Gulf coast in the state of Veracruz early on Saturday as a category two storm that could bring life-threatening floods.

In neighboring Guatemala, President Jimmy Morales spoke on national television to call for calm while emergency crews checked for damage.

"We have reports of some damage and the death of one person, even though we still don't have details," Mr Morales said. He said the unconfirmed death occurred in San Marcos state near the border with Mexico.

The quake occurred in a seismically active region near the point of collision between three tectonic plates, the Cocos, the Caribbean and the North American.

Mexico's National Seismological Service said the area has seen at least six other quakes of magnitude 7.0 or greater since 1900 - though three of those occurred within a nerve-wracking nine-month span in 1902/03.

Update 9.58am: A major earthquake off Mexico's southern coast has killed at least five people, with the president saying it was the biggest to hit the country in a century.

Houses toppled and the quake produced tsunami waves and sent people running into the streets in panic.

The US Geological Survey reported the earthquake's magnitude as 8.1, but President Enrique Pena Nieto said it was 8.2, making it the largest in Mexico for 100 years. He also said it was bigger than the one in 1985, when thousands were killed in four Mexican states.

"It was a large-scale earthquake," Mr Pena Nieto said. "It had a bigger magnitude than the one Mexicans knew in 1985."

He said 62 aftershocks followed the quake and it was possible one as strong as 7.2 could hit in the next 24 hours.

#Sismo #terremoto #earthquake #Mexico #mexicodf pic.twitter.com/t29dxICBlX

— Edward G. Robinson (@bulletorballot) September 8, 2017

The Pacific Tsunami Warning Centre said waves of 3ft (1m) above the tide level were measured off Salina Cruz, Mexico.

Smaller tsunami waves were observed on the coast or measured by ocean gauges in several other places. The centre's forecast said Ecuador, El Salvador and Guatemala could see waves of 3ft (1m) or less. No threat was posed to Hawaii and the western and South Pacific.

The massive 8.1-magnitude earthquake off the coast of southern Mexico has caused at least two deaths so far.

The quake was so strong that it caused buildings to sway violently in Mexico's capital, more than 650 miles (1,000km) away. Residents fled buildings, many in their pyjamas, and gathered in frightened groups in the street. Some neighbourhoods remained in darkness after electricity was knocked out.

M8.0 #earthquake (#sismo) strikes 200 km SW of Tuxtla Gutiérrez (#Mexico) 25 min ago. Updated map of its effects: pic.twitter.com/hKkngae5Yd

— EMSC (@LastQuake) September 8, 2017

Chiapas Governor Manuel Velasco said two women died on San Cristobal when a house and a wall collapsed. He urged people living near the coast to leave their homes as a protective measure.

"There are damages in hospitals that have lost energy," he said. "Homes, schools and hospitals have been damaged."

Lucy Jones, a seismologist in California who works with the US Geological Survey, said such a quake was to be expected.

"Off the west coast of Mexico is what's called the subduction zone, the Pacific Plate is moving under the Mexican peninsula," she said. "It's a very flat fault, so it's a place that has big earthquakes relatively often because of that."

"There's likely to be a small tsunami going to the south-west. It's not going to be coming up and affecting California or Hawaii," she said. "For tsunami generation, an 8 is relatively small."

Earlier: A massive 8.1-magnitude earthquake has struck off the coast of southern Mexico, toppling houses in Chiapas state, causing buildings to sway violently as far away as the country's distant capital city and triggering a tsunami warning.

The US Geological Survey said the quake struck at 11.49pm local time on Thursday and its epicentre was 102 miles (165km) west of Tapachula in southern Chiapas state, not far from Guatemala. It had a depth of 22 miles (35km).

The US Tsunami Warning System said hazardous tsunami waves were possible on the Pacific coasts of several Central American countries, including Guatemala, El Salvador, Costa Rica, Nicaragua, Panama and Honduras, within three hours.

Possible #tsunami alert for #Oaxaca & #Chiapas in #Mexico - Irish citizens should follow advice of local authorities @dfatravelwise https://t.co/QyytWiaZuZ

— Irish Embassy Mexico (@IrishEmbMexico) September 8, 2017

There was no tsunami threat for the US West Coast, but the warning system said waves could reach Mexico and as far as Ecuador.

"The house moved like chewing gum and the light and internet went out momentarily," said Rodrigo Soberanes, who lives near San Cristobal de las Casas in Chiapas, a poor largely indigenous state popular with tourists.

Chiapas Civil Defence said on its Twitter account that its staff were in the streets aiding people and warned residents to prepare for aftershocks. But it made no immediate comment about damage.

The quake was so powerful that frightened residents in Mexico City, more than 650 miles (1,000km) away, fled apartment buildings, often in their pyjamas, and gathered in groups in the street.

Buildings swayed strongly for more than one minute, loosening light fixtures from ceilings.

Helicopters crisscrossed the sky above Mexico City with spotlights. Some neighbourhoods kept electricity while others remained in darkness.In neighbouring Guatemala, President Jimmy Morales spoke on national television to call for calm while emergency crews checked for damage.

Local radio in the Central American country reported one death, but it could not be confirmed.

"We have reports of some damage and the death of one person, even though we still don't have exact details," Mr Morales said.

He said the possible death occurred in San Marcos state near the border with Mexico.

AP