A suspected suicide bombing killed 36 at a Shi'ite mosque in Pakistan's capital Islamabad on Friday, police and government officials said.

Local authorities fear the death toll from the attack, which occurred in the Shehzad Town area, may rise and have declared an emergency across the city's hospitals.

According to eyewitness accounts, a suicide bomber detonated an explosive device after being stopped at the Khadija Al-Kubra mosque entrance during Friday prayers.

Security forces, police and rescue teams cordoned off the site and launched a search operation following the blast.

Security has also been tightened across the capital and a formal investigation has been opened.

Pakistani Foreign Minister Ishaq Dar condemned the attack, vowing that "extremists will be brought to full account."