ISLAMABAD>> A suicide bomber targeted a Shiite mosque on the outskirts of Islamabad during Friday prayers, killing 31 people and wounding at least 169, officials said, a rare bombing in Pakistan’s capital as its Western-allied government struggles to rein in a surge in militant attacks across the country.

Television video and social media images showed police and residents transporting the wounded to nearby hospitals. Some of the wounded in the attack on the sprawling mosque of Khadija Al-Kubra were reported to be in critical condition.

Rescuers and witnesses described a harrowing scene, with bodies and wounded lying on the mosque’s carpeted floor. Hussain Shah said he was praying in the mosque courtyard when he heard a sudden, loud explosion.

“I immediately thought that some big attack had happened,” he said. He then went into the mosque to utter chaos — many of the wounded were screaming and crying out for help. Shah said he counted about 30 bodies inside the mosque, while the number of the wounded appeared to be significantly higher.

No one immediately claimed responsibility for the explosion, but suspicion is likely to fall on militants such as the Pakistani Taliban or the Islamic State group, which has been blamed for previous attacks on Shiite worshippers, a minority in the country. Militant groups across Pakistan often target security forces and civilians.

Although attacks are not so frequent in Islamabad, Pakistan has seen a surge in militant violence in recent months, largely blamed on Baloch separatist groups and the Pakistani Taliban, known as Tehrik-e-Taliban Pakistan, or TTP, which is a separate group, but allied with Afghanistan’s Taliban. A regional affiliate of the Islamic State group has also been active in the country.

In the initial aftermath of the explosion, a lower number of casualties was released, but Islamabad Deputy Commissioner Irfan Memon gave the latest tolls.

Pakistan’s Defense Minister Khawaja Mohammad Asif wrote on X that preliminary findings suggest the suicide bomber had been on the move to and from Afghanistan. Asif said the mosque’s security guards tried to intercept the suspect, who opened fire at them and then detonated his explosives among the worshippers.

The condition of the guards was not immediately known.

The Afghan Defense Ministry said Afghanistan condemned the mosque attack in Islamabad and said the Pakistani defense minister had “irresponsibly” linked the attack to Afghanistan.