Eyewitnesses reported seeing three injured people being removed from the scene after a explosion gutted four rooms in the building and destroyed a neighboring house, the Express Tribune said Sunday.
Police searched area hospitals for blast victims, but could not find them, the newspaper said.
Police surmise that those in the seminary were preparing explosives when the blast occurred, the report said.
Deputy Inspector Mohammed Jaffar said some religious literature was found at the site of the building, described as an unregistered seminary in Eastern Bypass, an area on the outskirts of the city where at least 12 people were killed and 50 were injured in two other explosions recently.
Beyonce flaunts bikini body, Blue Ivy in vacation pics
Couple mistakenly served bag of cash at McDonald's drive-thru