- via Getty Images Bomb squad personnel along with sniffer dogs scour the blast site for evidence following a low intensity blast from an Improvised Explosive Device (IED) which killed a woman and left three injured near a busy restaurant in the central business district of Bangalore, during late evening on December 28, 2014. AFP PHOTO/STR (Photo credit should read -/AFP/Getty Images)

NEW DELHI - The crude bomb blast in the heart of Bangalore that killed one woman and injured three others was a "terror attack" and the case could be handed over to the National Investigation Agency, the Centre today said. It has asked the Karnataka government to beef up security by increasing CCTV surveillance in the IT city.

Emerging from a high-level security review meeting, a day after the low intensity blast in Bangalore left a woman dead, Home Minister Rajnath Singh said an idea about the nature of the blast and who could be behind it could be ascertained only after a proper probe.

Minister of State for Home Kiren Rijiju said, "It was a terror attack." He said investigators were trying to piece together the leads and efforts were on to find out the people behind the blast. "It is too early to say anything on it. Investigation is on," he said when asked who could be behind the explosion.

The Home Minister said the Centre would provide all possible help to Karnataka in the Bangalore blast case and asked the state government to install adequate number of CCTVs in prime areas of the IT city.

"I appeal to the Karnataka government to install CCTV cameras as much as possible in as many places. It is too early to say who is behind this," he told reporters here.

Singh also appealed to all state governments, particularly those having major cities, to install maximum possible number of CCTV cameras in all prime locations.

"The central government is ready to provide all assistance to the state government in this endeavour," he said.

Asked about the possibility of handing over the blast probe to National Investigation Agency, Singh said a decision on it would be taken only after collecting the relevant information.

"If necessary, we will hand over the investigation to the NIA," he said. Official sources said two Central teams comprising investigators and explosive experts are being dispatched to visit Bangalore from Delhi and Hyderabad and they would join the local police in the blast probe.

The Home Minister said he reviewed the security situation in Karnataka and Assam, where NDFB militants killed more than 70 people last week, with top officials, including National Security Advisor Ajit Doval, Union Home Security Anil Goswami, Director of Intelligence Bureau Asif Ibrahim.

Meanwhile, Law Minister Sadananda Gowda and Chemical Minister Ananth Kumar met Rajnath and discussed with him the situation in the city in the aftermath of the blasts.

Bengaluru has been on a general alert since police picked up an engineer for allegedly running a pro-Islamic State Twitter account that had tens of thousands of followers worldwide. State police had received threats that there would be retaliation after the arrest of Mehdi Masoor Biswas.

Singh had called up Karnataka Chief Minister S Siddaramaiah last night and assured him of all help by the Centre.

Police said the low-intensity blast was triggered by an improvised explosive device (IED) placed between two flower pots near the Coconut Grove restaurant in the heart of the city’s busy Church Street area that was packed with Sunday evening crowds.

The attack sparked security alert in other cities, including Mumbai, Delhi and Pune, ahead of New Year’s celebrations, security officials said. Police commissioner MN Reddy said no group has yet claimed responsibility for the blast. "Essentially, it was aimed at causing panic and fear," Reddy told reporters.

A 38-year-old woman who was walking past the restaurant suffered shrapnel injuries to her head and neck and died in hospital later.

Siddaramaiah has announced a compensation of Rs five lakh to the kin of a woman who was killed in the explosion. Siddaramaiah, who had rushed to the blast site from Mysuru, said the best treatment would be provided to the injured.

Compensation would also be given to the injured.

The victim identified as Bhavani had come on a visit here from Tamil Nadu and was killed and three others, including one of her relatives, injured in the blast outside the restaurant around 8.30 pm.

Reddi confirmed that Bhavani, in her 30s, succumbed to injuries at Mallya Hospital, where she was rushed in a serious condition. Her relative Karthik, who was also injured, is hospitalised but out of danger. Two more injured - Vinay and Sandeep - are undergoing treatment at HOSMAT hospital.

The restaurant is close to the fashionable Brigade Road and MG Road, dotted with bars and restaurants with teeming crowd on weekends.

The IED was wrapped in a plastic bag, Karnataka Director General of Police L Pachau told reporters at the site. Police has cordoned off the area and mobilised the entire city police force stepping up security.

PTI quoted one of the injured, Vinay, as saying that they were coming out of the restaurant and were close to the woman, who died, when the blast occurred. He said he saw her slump to the ground.

Rijiju said the situation in Bengaluru was under control, but it was too early to say who was responsible for the explosion.

Asked if there was any threat perception to the city, Reddi said, "there has been threat perception in general, in view of the fact that there are festivities, in view of the fact that there has been New Year's eve coming..."

Police have recorded the statements of the owner and the guard of paan shop nearby, the Hindustan Times reported.

"Whatsapp msgs were circulated saying there could be blasts here and there including bus stations. No other blast has been reported in any other part of the city," HT quoted Reddi as saying.

A counter-terror official, requesting anonymity, told HT that the IED looks similar to the ones used in a blast in Uttarakhand's Roorkee district on December 6 near a venue of a Vishva Hindu Parishad meeting and the explosion in Pune outside a police station on July 11.

Reddi said there has been "some amount" of threat perception but that has been generic and there has been an alert in general. This is the fourth time the country's technology hub was hit by bomb blasts after incidents in 2008, 2010 and 2013.

In 2008, in serial blasts at nine places, two persons were killed and 20 others injured in an IED explosion. Two bombs exploded outside the cricket stadium hours before an IPL match, leaving 15 persons injured in 2010. A third bomb was defused.

In 2013, a bomb went off outside the state BJP headquarters in the crowded Malleshwaram area just ahead of the Assembly polls, leaving 16 people injured.