Hindu nationalists staged a strike Monday in protest at twin bombings linked to militants that killed 42 people here, accusing the Indian government of a "soft approach on terrorism".
The strike led by the main opposition Bharatiya Janata Party (BJP) in the southern city of Hyderabad kept many people from work and school in the mixed Hindu-Muslim city, still reeling from Saturday's carnage. India's home secretary Madhukar Gupta on Monday pointed the finger at foreign-based militant groups, echoing accusations made earlier by the government of Andhra Pradesh state, of which Hyderabad is the capital.
"We are probing all angles. It may be that Lashkar-e-Toiba, Jaish-e-Muhammad could be involved," Gupta said on news channel NDTV, naming two groups fighting an separatist insurgency in Indian-held Kashmir.
"The important thing is to find out who was involved both in the planning and the preparation as well as in the execution" of the blasts at a packed outdoor auditorium and a nearby food stall, Gupta added.
But the BJP, pointing to the failure to find those behind a string of deadly blasts around the country in the past year, said the government in New Delhi had not done enough to ensure security within India's borders.
"We have been constantly warning the centre (federal government) that it should take adequate measures to strengthen internal security, but the Congress-led government has never bothered to rein in terror," said senior BJP leader Vijay Kumar Malhotra.
The strike kept Hyderabad, a normally teeming city of 6.5 million people, quiet Monday, with about 2,500 state-run buses off the roads after 10 of them came under attack in the wake of the blasts. State-run and private schools declared a holiday after the BJP called the state-wide strike. Police received several telephone bomb threats, all of them apparently hoaxes.
Forensic experts were Monday studying the material used in the bombs which were set off by timers and left more than 50 wounded. "Yes, it is a timer-based explosive and one bomb that we defused, it also had a quartz clock timer," investigating officer Ram Mohan told NDTV.
Police recovered and defused one bomb found in a cinema a few hours after the twin blasts. Initial reports said police had recovered several more unexploded bombs across the city, but the claims were later denied.
The state's chief minister, Y.S. Rajshekhar Reddy, said that "available information" pointed to the involvement of terrorist organisations based in neighbouring Pakistan and Bangladesh.
He rejected any intelligence failure on the part of his government amid calls for his resignation in the wake of the second major terror attack in the city in less than six months. In May, 11 people were killed and 15 others were injured in a blast at a 17th century mosque.
No one has claimed responsibility for Saturday's attacks and no arrests have been made, but Indian newspapers quoted unnamed police officials as saying the Bangladesh-based militant outfit Harkatul Jihad Al-Islami was the main suspect.
Security services received intelligence reports five months ago warning that extremists were preparing to carry out bombings, The Hindu newspaper reported Monday.
Some eight kilos (nearly 18 pounds) of military-grade explosives had been delivered to a Harkatul cell, the report said quoting unnamed sources, noting police had failed to establish the targets or identities of the operatives.
Federal home minister Shivraj Patil said the government had "bits of information" before Saturday that an attack was being planned but did not know a "time and place."