ISLAMABAD, May 16 (Xinhua) -- At least 20 people were injured on Thursday when a blast hit a bank in Sadiqabad city of Pakistan's eastern Punjab province, an official said.

Deputy Commissioner of the area Jameel Ahmed Jameel told media that the blast took place in a private bank when around two dozen people, including staff and customers, were inside the bank located at the KLP road in Sadiqabad city of Rahim Yar Khan district.

Police and rescue teams rushed to the site and shifted the injured to the Shaikh Zayed Hospital where five of them were reportedly in critical condition.

The blast destroyed the bank partially and also damaged several vehicles parked outside.

Nature of the blast is not known yet. Police have cordoned off the area and launched an investigation into the incident.