|Pakistani Interior Minister Aftab Khan Sherpao (l)visits the site of the bombing|
Officials have offered a reward and released photos of the severed head of the suicide bomber who walked into Islamabad's Bari Imam Shrine during a Shi'ite Muslim religious festival and blew himself up.
While some Sunni Muslims were also at the festival, Interior Ministry authorities say they are investigating whether sectarian militants were involved in the bombing. Hundreds of people have been killed in reprisal attacks by Sunni and Shi'ite militants over the past decade and a half.
Pakistani President Pervez Musharraf condemned the suicide bombing as a heinous act of terrorism. A spokesman for U.N. Secretary-General Kofi Annan urged Pakistani authorities to spare no effort in bringing those responsible to justice.
No group has claimed responsibility for Friday's bombing.
Some information for this report provided by AFP and Reuters.