Several gunshots were heard after three armed militants entered the private five-star hotel.
The security guard was killed after he tried to stop the gunmen from entering the hotel's premises, the Inter-Services Public Relations (ISPR) said in a statement.
The Pearl Continental Hotel is frequented by both business and leisure travellers.
In the last few years, the BLA has been conducting several suicide attacks in Balochistan.
The group was also behind the attack at the Chinese Consulate in Karachi last year.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)