The illegally constructed four-storeyed Somnath building collapsed yesterday afternoon at Taljai Hill, Sahakar Nagar, killing six construction workers and injuring 17 others. Around three persons are believed trapped under the debris and rescue operations, including a dog squad has been pressed into service till late last night.

The incident took place at around 2 pm when construction work was going on. In moments, the structure collapsed like a stack of cards and around 15 workers, including the family of a watchman, were trapped under the debris.