A suicide bomber blew himself up at a mosque in Tarlai, Islamabad, on Friday, killing at least 31 worshippers and injuring more than 169, police sources said.

The attacker, described by police as a foreign national affiliated with the militant group Fitna al-Khwarij, was stopped by security personnel at the entrance gate of the mosque before detonating the explosive device, the sources said.

Authorities said the attack had no connection with Islam and condemned the targeting of worshippers, according to police sources.

President Asif Ali Zardari and Prime Minister Shehbaz Sharif condemned the blast, expressing deep sorrow over the deaths.

The president called targeting innocent citizens a crime against humanity and said the nation stands with the affected families.

He directed authorities to provide all possible medical facilities to the injured.

Prime Minister Sharif directed Interior Minister Mohsin Naqvi to conduct a thorough investigation and immediately identify those responsible, saying no one would be allowed to spread mischief and unrest in the country.

He also sought a report from the local administration and directed that the injured be provided with the best possible medical care.