NEW DELHI - Rescuers on Monday plucked two survivors from the ruins of a southern India apartment block that collapsed at the weekend, as they raced against the clock to find dozens more feared trapped in the rubble.
The confirmed death toll from Saturday's disaster on the outskirts of Chennai rose to 20 as the authorities blamed shoddy construction for what was the second deadly building collapse in India within a matter of hours.
Mr Karuna Sagar, a senior officer with the Tamil Nadu state police force said that, six people were arrested in the case on account of negligence, including the builder and his son, the architect of the residential tower and three others overseeing the building construction.
"Forty-three bodies were retrieved, of them 20 were dead and 23 were alive," Mr Sagar told AFP in a phone interview on Monday. "About 30 may be trapped (under the debris), but the exact number is not known yet," he added.
Reports said that two people rescued on Monday morning included a 35-year-old female construction worker who was one of several dozen entombed by a mass of concrete on Saturday night.
The woman had suffered a head injury, a hospital spokesman told the Press Trust of India news agency. A male co-worker was also being treated in hospital.
Emergency teams used mechanical diggers and heavy-cutting equipment to try and find more survivors in the ruins of what was a partially built 11-storey complex.
The National Disaster Response Force (NDRF) said more than 400 rescuers were taking part in the search and were "leaving no stone unturned to save lives of the victims... by making best use of the latest sophisticated equipment".
Mr Sagar said the rescue operation was being complicated by fears that the removal of debris in a rush could harm those trapped inside, and the operation had to be carried out systematically.
"The building has come down like a stack of cards," Mr Sagar told AFP.
Rescuers are cutting open boulders and going in with oxygen and lights, "wherever there is any indication of life", he added.
As the search for the missing entered its third day, voices from the wreckage were still being heard, Mr T. S. Sridhar, commissioner of the disaster management agency, told the NDTV network.
Although there was some rain overnight, temperatures at the scene are around 40 degrees, and rescuers are worried that survivors could succumb to fatigue.
Speaking on a visit to the scene of the disaster on Sunday night, Tamil Nadu Chief Minister Jayalalithaa Jayaram said the collapse appeared to have been the result of poor construction.
"From investigations conducted by our senior officers, it appears that the building plans that were approved were not strictly adhered to by the builders," she told reporters.
"There was nothing wrong with the plans that were submitted for approval but the builders... did not adhere to the plans that have been approved."
"It is too early to say exactly what went wrong but there appears to have been serious structural defects... Tests have to be conducted to see whether the soil is suitable, whether the soil is capable of bearing such a huge weight."
The collapse in Tamil Nadu on Saturday came only hours after a dilapidated apartment block crumbled in the capital New Delhi, killing 10 people including five children.
Building collapses are common in India. Lax regulations and the demand for cheap housing mean contractors sometimes use substandard materials or add unauthorised extra floors.
In September last year, more than 50 people were crushed to death when a five-storey building collapsed in India's financial capital of Mumbai on the west coast.