The bomb, hidden under a bench in the courtyard of the historic Mecca mosque, exploded during prayers Friday, killing 11 people. Another five were killed when clashes erupted between security officials and Muslim protesters after the blast and police opened fire on stone-throwing crowds.

Investigations continued Sunday, with a bomb disposal unit from the federal National Security Guard searching through the debris of the attack. They provided no details about the investigation.

Across the city shops reopened and life returned to normal, with fewer armed police guarding the streets.

"The city is peaceful and calm and the situation is normal," city police chief Balwinder Singh told reporters.

On Saturday, hundreds of police in riot gear were deployed throughout the mostly deserted streets, with most shops closed for a daylong strike called by Muslim groups.

There was no immediate claim of responsibility for the bombing but Indian media continued to report that intelligence agencies were looking at a possible link to Islamic militant groups based in neighbouring Pakistan, India's longtime rival.

The news reports offered no reasons why investigators would suspect Muslim groups in an attack on a mosque, but the militants are routinely blamed even when Muslims are targeted.

Such accusations stoke resentment among Muslims, who account for about 130 million of India's 1.1 billion people, about 80 percent of whom are Hindu.

Hyderabad, a city of 7 million people, about 40 percent of whom are Muslim, has long been plagued by communal tensions and occasional inter-religious bloodletting.