Islamabad, Pakistan (BBN)- At least two police officers were killed and four others injured in a suicide attack on a police emergency call center in the capital, Islamabad on Saturday, officials said.

The suicide bomber approached of police office located in downtown area of the capital and detonated explosives when security officers opened fire, police officials confirmed.

On early Saturday, two high-ranking prisoners were killed in a bomb and gunfire attack on a military convoy that was transporting prisoners.

The prisoners as Muhammad Alam and Ameer Izzat were arrested on Thursday, police said, adding that they were senior members of the militant group Tehrik-e-Nifaz-i-Shariat-e-Muhammadi.

BBN/ANS/SSR/AD-07June09-3:10 am (BST)