ISLAMABAD — A five-story residential building in Pakistan's southern port city of Karachi collapsed on Thursday, leaving at least three people killed and multiple others trapped, said rescue and medical officials.   

Confirming the death toll, Salma Kauser, senior director of medical and health services at Karachi Metropolitan Corporation, told Xinhua that 22 people were also injured when the residential building collapsed in Rizvia Cooperative Housing Society in Karachi, the provincial capital of south Sindh province.   

ALSO READ: Cambodia building collapse kills 36 people, injures 23

She said out of the 22 injured, at least five people are in critical condition, and are being treated in the intensive care unit at the Abbasi Shaheed Hospital.   

The building collapsed after the owner of the building started construction of another storey, local media reported.   

Rescue teams along with paramilitary force Rangers and police personnel rushed to the scene for rescue and relief operation. 

A contingent of civil engineers from the Pakistan army was also dispatched to the area to inspect the building which was reportedly illegally constructed about two years ago.   

Some 10 families were residing in the building. A clinic was also being run on the ground floor of the building and a good number of patients were visiting the clinic every day, according to local residents.

The building collapsed after the owner of the building started construction of another storey, local media reported.   

Two nearby buildings also sustained partial damage, said city administration officials, adding that the residents of one of the adjacent buildings have been evacuated after cracks emerged on it due to the building collapse.   

READ MORE: China condemns attack on consulate in Pakistan's Karachi

Sindh Chief Minister Syed Murad Ali Shah took notice of the building collapse and asked local government officials and Sindh Building Control Authority to submit a detailed report on the incident.

He also directed authorities concerned to ensure people are safely recovered from the debris and provide the best possible medical treatment to the injured.