A loud explosion has been heard in Islamabad , Pakistan 's capital . The blast was caused by a suicide bomber who blew himself up at the gate of an army base near the city center. Members of the police branch housed in the building help protect government officials such as the prime minister , CNN 's Reza Sayah said , and with the explosion , someone is `` trying to send another message to the federal government here in Islamabad . '' Blast came as Pakistanis celebrated their national day .
A loud explosion has been heard in Islamabad , Pakistan 's capital . The blast was caused by a suicide bomber who blew himself up at the gate of an army base near the city center. Blast came as Pakistanis celebrated their national day .