A family stay outside of their damaged home at the village of Huixtepec in Ometepec, in Guerrero State 

An earthquake measuring 6.3 struck south-western Mexico Monday, sending thousands of people into the streets of the capital in fear. There were no immediate reports of casualties or damage, reports AFP.

The quake struck at 1736 GMT with its epicentre located 158 kilometres (about 100 miles) from Huajuapan de Leon, in the state of Oaxaca, at a depth of 12.3 kilometres, the US Geological Survey said.

Residents said the quake rocked Mexico City, causing panicked people to flee houses and buildings in many areas of the capital. Thousands of people poured into the city's main downtown boulevard, Paseo de La Reforma.

But Mayor Marcelo Ebrard said on his Twitter account that there were no immediate reports of damage.

"We have an earthquake again. Evacuation under way," he said. "We have no damage yet."

Mexico City's police chief, Manuel Mondragon, said an initial survey of the city from the air and land had been completed "with no catastrophic situation to report."

Officials in Guerrero and Oaxaca states dispatched patrols to assess damage in rural areas near the epicentre which were already hit by a 7.4 magnitude quake on March 20, which killed two people and injured 13 others.

The earthquake -- with its epicentre south of the Pacific resort of Acapulco -- was the most powerful to hit the country since a deadly temblor in 1985, which destroyed entire neighbourhoods of Mexico City.

More than 40 aftershocks, some measuring up to 5.0 magnitude, shook the Mexican capital and southern areas in the aftermath of the March earthquake, according to the National Seismological Service.

People in Mexico's crowded capital -- with more than 20 million in the metro area -- are more than familiar with seismic activity and used to evacuation drills.