India Thursday said that all terror groups operating from the country or abroad are on the radar for the serial blasts that rocked Mumbai Wednesday which claimed the lives of at least 17 people and injured over 70 others.

Police check passengers at the airport in Mumbai, India, July 14, 2011. Police strengthened security in Mumbai airport as well as in several other cities after Wednesday's serial blasts, which killed at least 17 people and injured 131 others. (Xinhua/Li Yigang)

"We do not want to proceed with any kind of pre-supposition and speculate. All groups who have the capacity are suspected. All angles will be explored, leads will be followed without any predetermination of the cause," Indian Home Minister P. Chidambaram told the media in Mumbai. The Indian Home Minister also admitted there was no intelligence inputs related to Wednesday's blasts.

"There have been no inputs from the central and state agencies. This cannot be referred to as an intelligence failure since we keep talking to each other every hour. The group has worked in a clandestine manner and so could not be tracked," he said.

Chidambaram, however, said that preliminary investigation suggested that the blasts were not executed with the help of a remote trigger. "Ammonium nitrate has been used with a timer device. The three blasts were separated by an eight to 10 minute interval that shows it was a coordinated terror attack," he said.

The Indian government Thursday put all its metropolitan cities, including the national capital, on high alert following the serial blasts that rocked Mumbai. "The Indian capital, the southern cities of Hyderabad, Chennai and Bangalore, and the eastern city of Kolkata have been put on high alert. All the local governments have been asked to step up security," a senior government official said.

Indian Prime Minister Manmohan Singh and Congress chairperson Sonia Gandhi are due to visit the blast sites Thursday evening.

Meanwhile, the Anti-Terrorist Squad (ATS) of Mumbai said the home-grown terror group, Indian Mudjahideen's (IM) Bhatkal brothers are behind Wednesday's blasts.

The IM is also blamed for other terror attacks across India, including the Jan. 2010 attack against a German Backery restaurant in Pune, western India, which killed a dozen people, including foreigners.

The terror group also has the penchant to stage attacks on the date 13th and 26th, as most of the past attacks, including the 2008 Mumbai attacks, took place on these two dates, according to local experts.

VietNamNet/Xinhuanet