Pakistani security forces have been put on high alert in Islamabad and nearby Rawalpindi following reports that militants could carry out more suicide attacks in the twin cities.
The interior ministry alerted police in both cities about the possibility of more suicide strikes, following which security was further tightened.
Elite forces and policemen deployed at key sites have been provided with bulletproof jackets, officials said.
A suicide bomber blew himself up near the residence of Gen Tariq Majeed, chairman of Joint Chiefs of Staff Committee on October 30, killing seven persons and injuring over 20 in Rawalpindi.
The attack occurred a short distance from the residence and headquarters of President Pervez Musharraf.
Security forces in Islamabad and Rawalpindi have been on high alert since October 28, following reports that some suicide bombers had entered the cities to carry out attacks in the wake of the operations against militants in the Swat valley in North West Frontier Province.
Rawalpindi's Police Chief Saud Aziz said on Friday that the interior ministry had issued an alert about more suicide attacks in the city.
There is "solid evidence" about the involvement of Al Qaeda and local Taliban in the October 30 attack.
Though the suicide bomber is yet to be identified, there have been some "positive developments" in the probe, he said.
The bomber's head, legs and fingers had been found after the blast and sent for DNA test.
All exit and entry points of Rawalpindi are under observation.
Suspicious people are being watched as surveillance has been enhanced and vehicles are being checked thoroughly, Aziz said.