The earthquake which struck northern Iran on Saturday devastated a large area where houses are not made to withstand such mighty jolts.

Television footage showed buildings and homes in the Avaj district of Bou'in-Zahra which had been completely destroyed, with personal belongings strewn among the rubble.

When my father's body was removed from under the debris, his eyes were still wide open

Eight-year-old Qulam Alavi

But for the timing of the tremor, which measured 6.0 on the Richter scale, the death toll might have been much higher.

In the past, the worst casualties have been caused when earthquakes have occurred at night when everyone was asleep indoors.

This time it was early morning and many of the men had gone to work and the children to school.

Husbands ran back from the fields and vineyards to find their womenfolk entombed.

In the 20 villages worst affected, at least half the buildings have been razed to the ground.

In some villages, only one in 10 homes have been left standing.

People whose houses did survive have been advised to sleep outdoors because of the risk of aftershocks.

Homes destroyed

One of the worst-hit villages was Abdareh, about 225 kilometres (140 miles) west of the capital, Tehran.

There, 40 homes collapsed, killing at least 20 people, and the mosque fell down.

Buildings were not made to withstand earthquakes

A recovery-worker in a bulldozer, his face covered in dust, said he had excavated about 10 bodies from the rubble.

Tehran resident, Abbas Mohammedi, had travelled from the capital to visit his nine relatives in Abdareh, but he arrived too late.

"I came all the way to say hello to them all, and now I am here to bury them," he said.

Eight-year-old Qualm Alavi stood traumatised in front of the ruins of the house where he had lost both his parents.

"When my father's body was removed from under the debris, his eyes were still wide open," he said.

In the village of Esmailabad, 10km (six miles) north of Avaj, 38 people died and many more were trapped under tons of wreckage.

Women squatted in the dust, wailing as they rocked back and forth; a man poured earth on his head, crying "I've lost everyone."

Neighbours said his daughter and two grandchildren were dead.

Rescue effort

Hampered by aftershocks, the emergency teams have continued to look for survivors - and recover bodies.

Villagers have been sifting through rubble by hand

The Iranian Red Cross has deployed helicopters and sniffer dogs, but most of the rescue work is being done by the villagers themselves.

Men are digging through mounds of grey rubble, some with long-handled shovels, others with their bare hands, desperate for signs of life.

At least 500 people were killed in the earthquake and about 12,000 left homeless.

More than 2,000 people were injured and local officials say the number of casualties is rising, as seismologists warn of more aftershocks to come in the weeks ahead.