According to the latest figures, more than 4,000 people were killed and at least 19,000 injured in the massive earthquake that rocked north-west Turkey in the early hours of Tuesday morning.

Some survivors are still being pulled from collapsed buildings, but it is a race against time to find the thousands of people still missing.

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With more than 40 hours now having passed, it is feared that many trapped in the rubble of collapsed buildings will succumb to the intense heat and lack of oxygen.

And for many hope has already gone.

Across the quake zone, survivors identify and reclaim the bodies of dead relatives - or wait for search teams to recover the dead from flattened buildings.

Foreign assistance has arrived in the form of expert rescue teams, armed with the special equipment needed to detect the presence of living people under the rubble.

But there is also anger being expressed by those who survived at the slow arrival of help and equipment needed.

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Throughout the region, tens of thousands of survivors face another night sleeping outside, slowly coming to terms with the scale of the tragedy and frightened of further aftershocks.

Some are homeless, but others are wary of returning to homes which they consider unsafe.

The government is facing an uphill task trying to alleviate those fears. It is facing criticism on several fronts - for the speed and sophistication of its aid efforts and for its standards of housing.

The quake has been assessed at having measured 7.4 on the Richter scale - higher than originally thought.

And aftershocks measuring up to five on the Richter scale were still being felt more than 24 hours after the initial shock.

Widespread devastation

The quake, thought to be one of the most powerful this century, struck a densely-populated area of the country.

It caused widespread destruction from Istanbul to the port of Golcuk about 130km (80 miles) to the south-east, where up to 10,000 people are believed to be trapped.

(Click here to see a map of where the earthquake struck)

BBC Correspondent Chris Morris, who managed to travel to Golcuk, says that on every street, apartment blocks have crumbled into dust.

At least 200 people are missing in the ruins of a naval base destroyed by the quake.

They include senior naval officers who had assembled for a meeting at the base.

In many places, he says, rescue efforts are only just getting under way, and some sites remain almost untouched.

Oil fire still raging

Firefighters struggling to contain oil refinery fire

Officials in the nearby industrial town of Izmit say fire-fighters are still struggling to gain control of a huge fire which has been raging at Turkey's largest oil refinery.

The fire has engulfed six of the refinery's 30 oil tanks, and the governor of the region, Memduh Oguz, warned there was a danger it might spread and cause a new disaster.

Army fire-fighting aircraft carrying special chemicals joined local teams, and several foreign planes were also due at the refinery.

But local television showed huge flames still billowing up into the sky early on Thursday morning.

Israel, Japan, Germany, the United States, Britain and Russia have been sending groups of experts in search and rescue, and sniffer dogs.

They are bringing with them equipment sensitive to heat and to carbon dioxide - both signs of living people trapped beneath the rubble.

Even Turkey's traditional rival Greece has offered to send specialist personnel and hospital equipment.

Compensation promise

Seven affected provinces have been declared a disaster zone, enabling the government to commandeer all private and public facilities for the relief effort.

Architecture professor Neshdet Teymur on Istanbul's weak buildings

The government has also promised compensation to victims of the quake.

But already, many residents are beginning to express anger at the poor construction methods and lax safety standards that produced buildings unable to withstand such a tremor in a known earthquake zone.

Are you in the earthquake zone? Click here to send us your account.

Read the accounts of those who experienced the earthquake by clicking here

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