At least one person was killed on Monday in an explosion close to a police station in Islamabad, witnesses said.
TV footage from the scene of the blast late Monday showed a body under blanket.
A witness told Dawn TV news that the explosion took place close to a police station near a market in Islamabad. It was heard across much of the downtown area.
The source of the explosion was not immediately clear. Pakistan has seen a series of attacks by Islamist militants in recent years, including several in the capital.
Last September, more than 50 people were killed in a suicide truck bomb attack on the Marriott Hotel in the city.