A hand grenade was found early on Saturday at a playground near Pakistan Prime Minister Shaukat Aziz's home, in a third incident in the last 10 days of rockets and grenades being unearthed in the capital's VVIP area.
Sikandar Hayat, senior superintendent of Islamabad Capital Territory (ICT) police, said the hand grenade was old and unable to explode. Some children in the playground saw it and alerted the police.
The authorities have sought to exercise extra vigilance in the wake of suicide terror attacks carried out at the Capital's Marriott Hotel on January 26 and another at the Islamabad International Airport.
Last September, rockets were found close to the presidential palace, the prime minister's residence and en route to the army headquarters.
There have been at least three known attempts on the life of President Pervez Musharraf and one on Aziz. Militants, some of them known to have links with the armed forces, have been caught and are under trial. There has also been a conviction, pending appeal before a higher court.