At least six people were crushed to death and 12 others injured when a building collapsed in the southeastern Nigerian oil city of Port Harcourt, officials said on Sunday. They said more bodies may be trapped in the rubble of three-storey building, still under construction in the city centre where about 65 people were working when it collapsed in the early hours of Saturday, according to Reuters. Newspaper reports put the death toll at between 11 and 45. Rescue workers were still digging for more bodies and possible survivors on Sunday. "We have recovered six corpses from the wreckage, 12 people were rescued and taken to hospital and we are still clearing the rubble," said Godwin Bebe-Okpabi, special adviser to the Rivers state governor on emergency relief. Officials said authorities have ordered the arrest of the owner of the building for flouting a directive to suspend work on all such structures, after about 10 people were killed in May when another building in the city caved in. The collapse of buildings is common in Africa's most populous nation of about 140 million people. Authorities blame that on the use of sub-standard building materials and non-adherence to regulations.