Police have arrested three key suspects in connection with a blast in a park near Pakistani President Pervez Musharraf's army residence in Rawalpindi, police said on Tuesday.
"They are key suspects and were travelling in a car when we caught them at a temporary checkpost," senior officer Sikandar Hayat told the agency.
The latest arrests over the incident three weeks ago took place close to Islamabad's boundary with the neighbouring garrison town of Rawalpindi.
One of those arrested was the son of a retired brigadier, Hayat said. He did not say if the arrested men were affiliated to any known militant group.
Police had already arrested eight other suspects linked to a series of security scares, starting with the blast caused by a small homemade bomb in a Rawalpindi park on October 4.
On October 5, police found two Russian-made rockets hooked up to mobile phones hidden across a six-lane road from parliament and the presidency in Islamabad.
A couple of days later, two more rockets were found hidden on a hill in the capital near military intelligence headquarters.