Security forces stand guard outside the Data Ganj Baksh shrine in central Lahore, one of Pakistan's most famous Sufi shrines, after bomb blasts ripped through the building, killing dozensPhotograph: Arif Ali/AFP/Getty Images

Shrine volunteers carry away one of the many victims. Thousands of people had gathered to pray, dance and listen to devotional music when the bombs went offPhotograph: Rahat Dar/EPA

Security forces examine the scene of the attack. The Data Ganj Baksh shrine, one of Lahore's most famous and revered landmarks, is devoted to Hazrat Usman Hajwery, a 12th-century mystic popularly considered to be the spiritual protector of the cityPhotograph: Arif Ali/AFP/Getty Images

A man injured in the attack sits in an ambulance. The suicide bombers struck on Thursday night, the shrine's busiest time Photograph: Rahat Dar/EPA

Security officials and rescue workers inspect the scene of the bomb blasts. It was the second assault on a religious site in Lahore in recent months – an attack on members of the minority Ahmadi sect in late May killed 94 peoplePhotograph: Rahat Dar/EPA

Security forces pick through debris inside the shrine

Volunteers and emergency services at the blood-stained marble courtyard of the shrine, where thousands had gathered to pray Photograph: Arif Ali/AFP/Getty Images

Family members of victims comfort each other Photograph: KM Chaudary/AP

A local worshipper looks at the aftermath of the attack on the Data Ganj Baksh shrine. This deadly assault is not the first attack on Sufis in Pakistan. In March 2009 extremists in Peshawar blew up the shrine to Rahman Baba, the most celebrated Sufi of the North-West Frontier region. Photograph: Arif Ali/AFP/Getty Images

Policemen stand guard at the shrine

A man at a hospital in Lahore discovers that a relative is among the many victims of the bomb blasts that ripped through the Data Ganj Baksh shrinePhotograph: Arif Ali/AFP/Getty Images