Security forces yesterday searched for explosives at two locations in and near the southern city of Hyderabad, after twin blast there blamed on Islamic militants killed 42 people on Saturday.
Sniffer dogs and bomb disposal teams were rushed to the state secretariat in Hyderabad, which houses the ministries and offices of the Andhra Pradesh state government.
"We are searching the area after we got a call that explosives have been planted here," said a police official, who declined to be named.
A search was also underway at a hotel in Secunderabad, which is separated from Hyderabad, the state capital, by a lake.
Earlier yesterday, an unclaimed bag at a private hospital in Hyderabad created panic among a few hundred people at the facility. Police said the bag contained clothes.
The Bharatiya Janata Party (BJP) accused the government of security lapses that led to the devastating Saturday night bombings, after 11 people had died in a similar blast at a Hyderabad mosque in May.
The party called the strike in protest at the explosions, which ripped through a packed street eatery in the mixed Hindu-Muslim city and an amusement park where hundreds of people were watching a sound and light show.
"We have been constantly warning the center [government] that it should take adequate measures to strengthen internal security, but the Congress-led government has never bothered to rein in terror," senior BJP leader Vijay Kumar Malhotra said.
He accused the ruling coalition of a "soft approach on terrorism."
Hyderabad, a normally teeming city of 6.5 million people, was quiet yesterday morning, correspondents said.
State-run and private schools declared a holiday after the BJP, which is India's main opposition, called the stoppage across Andhra Pradesh state.
However, thousands of Hindu weddings took place as planned on Sunday, an auspicious day for Hindus, local priests said.
Forensic experts were studying the material yesterday 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 the NDTV network.
Police also recovered and defused one unexploded bomb from a movie theaters a few hours after the twin blasts.
Initial reports said police recovered several more unexploded bombs across the city, but this was later denied.
Indian investigators immediately said they suspected Islamic militants of the attack.
Y.S. Rajshekhar Reddy, the state's chief minister, said that "available information" pointed to the involvement of terrorist organizations based in Pakistan and Bangladesh.
He rejected any intelligence failure on the part of his government.
No one has claimed responsibility for the attacks and no arrests have been made, but Indian newspapers quoted unnamed police officials as saying the main suspects were the Bangladesh-based militant outfit Harkatul Jihad Al-Islami.
Security services had intelligence reports five months ago warning about extremists preparing for bombings in Hyderabad, the Hindu newspaper reported yesterday.
Some 8kg 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.