At least 19 people were killed and over 40 others injured in a blast that ripped through a gambling club in the old city of Karachi in southern Pakistan late Thursday night, reported local Urdu TV Express.

According to the report, the blast took place at about 9:35 p.m. when some unknown people threw two hand grenades into a gambling club in the Liyari area, an old town in Pakistan's southern port city of Karachi.

Earlier reports by some of the local media said that the blast was of a suicide nature, but most of the local media reports said that it was an attack by hand grenades.

All the injured people have been shifted to the Jinnah Hospital following the blast. Hospital sources said that about 30 out of the 40-odd people injured were in critical conditions and the death toll could further rise.

Police have cordoned off the area shortly after the blast was reported and a search operation is under way.

No group has claimed the responsibility for the blast yet.