At least six people were killed when a three-storey residential building collapsed in Karachi's Liaquatabad area in the early hours of Tuesday, rescue sources said.

The dilapidated building in Liaquatabad No 9 collapsed at around 2am, also injuring nine people including four women who were trapped under the rubble.

Rescue workers pulled out the survivors and bodies from under the rubble and shifted them to the Abbasi Shaheed Hospital and Jinnah Postgraduate Medical Centre (JPMC), while it is feared that some victims are still trapped.

According to area residents, the 60-80 yard building was in a derelict state and its third storey had been illegally built a few months earlier.

Area residents said four families had been residing in the building, which had tea and paan shops on its ground floor.

A large number of rescue workers, police officials and Rangers personnel took part in the rescue operation.

Talking to DawnNews, Deputy Commissioner Central Capt (retired) Fariduddin Mustafa said all machinery required for the rescue operation is present at the collapse site. He said it could take up to 24 hours to remove the debris after an incident of this nature.

Mustafa confirmed that three bodies had been pulled out of the rubble, adding that rescue officials were avoiding use of heavy machinery keeping in view the possible presence of additional survivors in the debris.

The DC said the public lacked awareness regarding construction of multi-storey buildings on small areas and the Sindh Building Control Authority is responsible for keeping an eye on the issue.

The collapsed building was not part of the list of Karachi's 300 dilapidated buildings, Mustafa said.

Safety codes are often ignored in Pakistan and in some of the poorer areas construction is haphazard and bribes are paid to inspectors to approve substandard construction.