No group has yet taken responsibility for three simultaneous bombings which have killed at least 20 people and wounded many more in Mumbai, India’s financial capital.

The bombs were detonated at the Zaveri Bazaar near a Hindu temple, in a taxi at Dadar, and at Mumbai's Opera House 0 suggesting the blasts were meant to kill the maximum amount of people.

This was a coordinated attack by terrorists, Home Minister P. Chidambaram told reporters in New Delhi.

The entire city of Mumbai has been put on high alert. I would appeal to the people of Mumbai and people all over the country to remain calm,

The worst terror attack on the city since November 2008 has also placed New Delhi and Calcutta on high alert and spawned speculation over who could be behind the carnage.

According to The Long War Journal, one of the top suspects behind the blasts are a mysterious group called Indian Mujahideen – which Indian intelligence officials believe might be a front for the Bangladesh-based militant group Harkat-ul-Jihad-al-Islami (HUJI-B), which is affiliated with al Qaeda affiliate.

The Journal report stated that Indian Mujahideen was created by HUJI-B in order to confuse investigators and to cover the tracks of another group called the Students Islamic Movement of India (SIMI), which allegedly provides logistics for the terrorist attacks.

Moreover, SIMI is allegedly an Indian front organization for the Harkat-ul-Jihad-al-Islami and Lashkar-e-Taiba and receives support from Pakistan's intelligence agency, Inter-Services Intelligence (ISI) and is also connected with al-Qaeda affiliate.
Lashkar-e-Taiba (LeT), which is now banned in Pakistan, was found to be behind the November 2008 attacks in Mumbai (with ISI also implicated).

Adding to the intrigue, a report in The Times of India suggested Wednesday’s bomb blast might have been a birthday present for Ajmal Kasab, the only member of the 2008 LeT crew who attacked Mumbai. Kasab is currently sitting on India’s Death Row for that prior attack.