Sept 13 (Reuters) - Five bombs exploded in crowded markets and streets in the heart of New Delhi on Saturday, killing at least 20 people and injuring 90 people.

The Indian Mujahideen Islamic militant group, which has claimed several major attacks in recent months, said it was responsible.

Following are some facts about the group:

ORIGINS

* The Indian Mujahideen first emerged in the wake of bombings in the northern state of Uttar Pradesh in November 2007, sending an e-mail to media outlets just before some of the bombs exploded.

* Indian police say the Indian Mujahideen is an offshoot of the banned Students' Islamic Movement of India (SIMI), but that local Muslims appear to have been given training and backing from militant groups in neighbouring Pakistan and Bangladesh.

SIMI has been blamed by police for almost every major bomb attack in India, including explosions on commuter trains in Mumbai two years ago that killed 187 people.

* The sophistication of the attacks appears to have caught police and intelligence networks unawares. Some of the bombings bore the hallmarks of the Bangladeshi militant group Harkat-ul-Jihad al Islami.

CLAIMS AND THREATS

* Another e-mail was sent in the name of the Indian Mujahideen after bomb attacks in May in the tourist city of Jaipur that killed 63 people. The email declared "open war against India" and included the serial number of one of the bicycles on which the bombs were left.

That e-mail, signed by "Guru Al-Hindi", said India would face more attacks in tourist sites if it did not stop supporting the United States in the international arena.

* Shortly before a series of bombs exploded in Ahmedabad, the capital of the western state of Gujarat, last July 26, an e-mail in the name of the Indian Mujahideen was sent to local media warning that people would soon "feel the terror of death" in the name of Allah. Those blasts killed 45 people.

It said the attacks were revenge for the Gujarat riots of 2002, when around 2,500 people, most of them Muslims, were killed by Hindu mobs.

* A later e-mail accused the state governments of Rajasthan, Uttar Pradesh, Madhya Pradesh, Andhra Pradesh, Karnataka and Maharashtra of harassing, imprisoning and torturing Muslims and threatened consequences if they did not stop.

It also told media outlets, especially the Times of India and Times Now, to stop their "propaganda war" against Muslims, and warned Mukesh Ambani, chairman of Reliance Industries <RELI.BO> and one of the world's richest men, to think twice before building a luxury 27-storey home on land in Mumbai previously owned by a Muslim charity.

ARRESTS

* Four weeks ago Indian police arrested 10 people who they said were behind the Ahmedabad bombs.

Police said one of those arrested, Abu Bashir, was the mastermind of the bombings and that all the suspects were active members of SIMI. (Writing by Kevin Liffey, London World Desk)

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