ISLAMABAD: Authorities in Pakistan's capital Islamabad are investigating the water in the city's main reservoir after tons of dead fish were found in a lake on the city's outskirts.

Police officer Imran Haider says Saturday samples of water and dead fish from Rawal Lake have been collected and sent for forensic testing after a complaint received from the capital's fisheries department.

According to Haider, Mohammad Sadiq Buzdar of the fisheries department said there has been an increasing number of dead fish in the lake since monsoon rains water began three days earlier.

Police and the fisheries department have not yet issued any alert regarding the situation.

Rawal Dam is one of two that enable water reservoir lakes for the capital.