A 6.1-magnitude earthquake struck off the coast of Ecuador on Wednesday, sowing new panic four days after a more powerful quake killed more than 525 people, with hundreds still missing.

The latest quake struck just off the coastal town of Muisne in northwestern Ecuador. No new damage or casualties were immediately reported, AFP journalists in the region said.

But tremors still jolted nerves even as rescue workers continued pulling bodies from the rubble of Saturday's 7.8-magnitude earthquake, Ecuador's worst in nearly 40 years.

The death toll from that quake crossed a new threshold as officials reported 525 deaths in the western province of Manabi alone - not including at least two deaths in the southwestern province of Guayas.

The previous toll given by officials was 480 deaths and some 1,700 missing.

Officials warned the toll was likely to rise further as emergency workers combed the mangled rubble, often by hand or with basic tools.


Rescuers walk along a street as they search for victims in Pedernales

At least 11 foreigners were killed in Saturday's quake, which struck a coastal region popular with tourists. They included citizens of Britain, Canada, Ireland and several Latin American countries.

Ecuadoran authorities called the latest quake an aftershock.

The US Geological Survey said it struck at 0833 GMT at a depth of 15.7 kilometers. It placed the epicenter 25 kilometers west of Muisne.

Losing hope  

Sniffer dogs and mechanical diggers were busy at work in the wreckage of coastal towns such as Pedernales and Manta, as the stench of rotting bodies grew stronger in the tropical heat.

Hope of finding more victims alive was fading fast as the crucial three-day mark came and went late on Tuesday.

Locals in devastated towns such as Manta - population 253,000 - were starting to lose patience.

"The rescue has been very slow and precious lives have been lost," said Pedro Merro, who said his cousin was under the wreckage of a three-storey market.

Luis Felipe Navarro said he was sure there were people alive in the concrete and twisted metal of a building he owned - one of around 800 structures toppled in the quake.

"I have received messages on my telephone. They say there are 10 of them in a cavity," he said. "But the rescue teams will not listen to me."

Makeshift morgues  

"It is very hard, but we are moving forward," President Rafael Correa told AFP in Manta, where he handed out food and water in what resembled a war zone.

In a glimmer of good news, he said 54 people had been rescued alive from the rubble.

Some 4,600 people were injured in the quake, according to government figures.

Hundreds of emergency workers from Colombia, Mexico, El Salvador, Spain and other countries were helping overwhelmed Ecuadoran officials.

Fears rose for thousands of people left homeless by the quake, prey to disease-bearing mosquitoes and dirty drinking water.

In Pedernales, some 180 kilometres north of Manta, a football pitch was serving as a makeshift morgue, as well as a medical and distribution center.

But not everyone was able to get help.

"We came here to ask for food but they've already handed out the supplies," Gema Guillen, a mother of three, told AFP.

The family had lost their home in the quake and was now sleeping on the floor, she said.

Correa said rebuilding will cost up to $3bn and could take two or three years.

Noises in the rubble  

In Manta, two young women with eyes red from crying wandered near a ruined hotel on Tuesday.

"My brother Irvin is under there," said Samantha Herrera, 27. "The firefighters only arrived this morning. Ecuador is not prepared for such a catastrophe."

Firefighting captain Freddy Arca said a couple with a two-month-old baby was trapped inside, as were as many as nine other people.

Rescuers said they could hear a noise from someone under the wreckage.

Arca ordered the skinniest member of his team to wriggle into a gap in the rubble.

The man came back up looking pale. Searching for survivors, he found two dead bodies.

"But we can still hear the noise," Arca said.