Officials said the attackers first hijacked a car then opened fire at a bus station before entering the police station. They were armed with automatic weapons and dressed in military fatigues.
The six victims included 4 policemen, one of whom was police superintendent Baljit Singh, and 3 civilians.
Gurdaspur is a vast rural district not as prosperous as other districts in Punjab, making it an unusual choice for an assault such as this one. It is however one of the most populous districts.
A junior minister suggested the attackers may have come across the border from Pakistan as there have been earlier reports of cross-border infiltration.
The Pakistan foreign ministry condemned the attack and extended its sympathies and condolences to the government and people of India.