People transfer an injured man to a hospital in southern Pakistani port city of Karachi, May 6, 2011. At least five people were killed and 18 others injured in a blast that took place Friday night in Karachi, the largest industrial city in Pakistan, reported local Urdu TV channel News 5. [Arshad/Xinhua]

At least five people were killed and 18 others injured in a blast that took place Friday night in Karachi, the largest industrial city in Pakistan, reported local Urdu TV channel News 5.

According to the report, the blast took place at about 9:10 p.m. local time when an unkonwn person hurled a hand grenade into the crowds gathering at an outdoor gambling den in the Layari area of Karachi.

Some local media reported that two hand grenades were hurled into the crowds.

On April 21, another gambling den was attacked by unknown people in the same city, in which 19 people were reportedly killed and more than 40 others injured.

The attack could be related to personal enmities instead of terrorism, said a local report.