A strong new earthquake shook Mexico on Saturday, causing fresh alarm in a country reeling from two even more powerful quakes this month that have killed nearly 400 people.

The US Geological Survey said the magnitude 6.1 quake was centred about 11 miles south-southeast of Matias Romero in the state of Oaxaca, which was the region most battered by a magnitude 8.1 quake on September 7.

It was among thousands of aftershocks recorded in the wake of that earlier quake, the most powerful to hit Mexico in 32 years, which killed at least 90 people.

There were some early reports of damage.

Bettina Cruz, a resident of Juchitan, Oaxaca, said by phone with her voice still shaking that the new quake felt “horrible”.

“Homes that were still standing just fell down,” Ms Cruz said. “It’s hard. We are all in the streets.”

Mexico CityRescuers have been working round the clock to save those trapped in the rubble (Rebecca Blackwell/AP)

Ms Cruz belongs to a social collective and said that when the the new shaking began, she was in a truck carrying supplies to victims of the earlier quake.

Nataniel Hernandez said by phone from Tonala, in the southern state of Chiapas, which was also hit hard by the earlier quake, that it was one of the strongest movements he has felt since then.

“Since September 7 it has not stopped shaking,” Mr Hernandez said.

Buildings and street signs swayed and seismic alarms sounded in Mexico City, prompting people with fresh memories of Tuesday’s magnitude 7.1 quake, that has killed at least 295 across the region, to flee homes and hotels. Some were in tears.

Alejandra Castellanos was on the second floor of a hotel in a central neighbourhood and ran down the stairs and outside with her husband.

“I was frightened because I thought, not again,” Mrs Castellanos said.

Pablo Vega Rodríguez Pablo Vega Rodríguez listens to his mobile as he waits for news on his cousin Paulino Estrada in Mexico City (Rebecca Blackwell/AP)

Mexico City mayor Miguel Angel Mancera told Milenio TV there were “no new developments” due to the quake, though he acknowledged that it provoked “some crises of nerves” among residents.

At the site of an office building that collapsed on Tuesday and where an around-the-clock search for survivors was continuing, rescuers briefly left the top of the pile of rubble before returning to work.

As rescue operations stretched into day five, residents throughout the capital have held out hope that dozens still missing might be found alive.

More than half the dead – 157 – perished in the capital, while another 73 died in the state of Morelos, 45 in Puebla, 13 in Mexico State, six in Guerrero and one in Oaxaca.