British rescue teams in Adapazari have been asked to pull out to allow bulldozers to move in, clearing still buried bodies to prevent the spread of disease.

Speaking after one of its last searches, in which the bodies of two dead children were uncovered, the British Rapid UK Rescue Team told of a dwindling number of survivors.

The BBC's Chris Morris in Izmit: "Time has run out"

Rescuer Barry Sessions said: "We have to pay for all the living people we get with all the dead people - that is the down side of it, it is a sort of trade off.

"As it goes on I am afraid we find more dead people, that is the way it is."

On Saturday, the British team worked frantically to reach two teenagers buried alive under a building.

Turkish authorities had issued a deadline for rescue efforts to cease. As the minutes ticked away, the Rapid UK team dug tunnels into the compacted layers of cement and crushed floors.

But the search had to be abandoned after the tapping noises stopped.

The team's leader Graham Payne spoke of fears that further deaths would be brought about by epidemics of typhoid, cholera, dysentery and hepatitis.

He said sewers were leaking and thousands of people were sleeping rough with no sanitation.

Quarantine hold-up for dogs

As the British rescue workers began their homeward journey, Rapid UK said it would call for special dispensation so that its dogs would not have to spend six months in quarantine.

John Holland, Rapid UK's deputy director, said the team's border collies Gemma and Kelly were "basically life savers and it is ludicrous to have them locked up for six months".

The dogs, who found three survivors buried alive under rubble, have pet passports, are microchipped and have had all the necessary vaccinations, he said.

"It depletes our capabilities in dealing with any other tragedy in the next six months," he added.

But Minister for Agriculture Nick Brown said: "It is impossible for us to relax the quarantine regulations for dogs coming in from a country where virulent, contagious rabies is endemic."

Rain could worsen conditions for homeless

The official death toll is currently about 12,000, but with 30,000 people still missing, it is feared the final toll could be as high as 45,000.

On Saturday, seven survivors who had spent five days trapped in the rubble, were rescued.

Among them were an 11-year-old girl, pulled from the wreckage of a four-storey building, a 10-year-old Israeli girl, two elderly women, two sisters aged 10 and 19, and a nine-year-old boy.

Two Britons are known to have been killed by the earthquake.

Father-of-two Lieutenant Commander Jim Acton, 37, based at Portsmouth, had survived the initial shock, but died on Friday after being flown back to the UK for treatment on his injuries.