Minutes after the blast at the 17th-century Mecca Masjid, worshippers who were angered by what they said was a lack of police protection began chanting "God is great!" Some hurled stones at police, who dispersed them with baton charges and tear gas.
While the situation at the mosque was quickly brought under control, Muslims later clashed with security forces in at least three parts of Hyderabad, said Mohammed Abdul Basit, police chief of Andhra Pradesh state, where Hyderabad is located. Police fired live ammunition and tear gas to quell the riots, killing two people, he said.
The bombing, which killed 11 people and wounded 35, and clashes raised fears of wider Hindu-Muslim violence in the city, which has long been plagued by communal tensions and occasional spasms of inter-religious bloodletting.
Many of those injured in the explosion at the Mecca Masjid were severely wounded, and the city's police chief, Balwinder Singh, warned the death toll could rise.
Soon after the blast, Y.S. Rajasekhara Reddy, the chief minister of Andhra Pradesh state, where Hyderabad is located, appealed for calm between Hindus and Muslims.
"This is an intentional sabotage on the peace and tranquility of the state," Reddy said of the bombing. "Every sane person has to unequivocally condemn this sort of incident. ... I take this opportunity to appeal to everyone concerned to show restraint."
Reddy told reporters in New Delhi, where he was meeting with federal officials on unrelated business, that one bomb went off around 1:30 p.m. local time and that police soon after found and defused two other bombs in the area of the mosque.
The bomb, made of a stick-grenade packed into a metal pipe, was detonated by a mobile phone attached to the device, said the state's police chief, Mohammed Abdul Basit.
Neither he nor any other officials gave any indication of who they suspected in the attack.
About 10,000 people usually attend Friday prayers at the mosque, located in a Muslim neighborhood of Hyderabad. The explosion sparked a panic.
"I was very close to the spot of the blast," said Abdul Quader, a 30-year-old who sustained light injuries to his legs.