Oct. 31 (Bloomberg) -- United Nations Secretary-General Ban Ki-moon condemned 12 bomb blasts that tore through the northeastern Indian state of Assam yesterday as the death toll from the attacks rose to 75 people with about 300 injured.

``There can be absolutely no justification for such indiscriminate violence,'' Ban, who was in New Delhi, said in a statement issued through his spokesman. The secretary-general ``strongly condemns this act of terrorism targeting civilians.''

Devices containing high-intensity explosives were detonated between 11 a.m. and noon and targeted crowded areas in Assam, state Health Minister Himanta Biswa Sarma said.

One unknown group calling itself the ``ISF-IM'' claimed responsibility for the attacks to a local news channel, Khagen Sharma, inspector general of police of Assam, said today by phone. Police are verifying the claim and investing the case from various angles, he said.

Police today interrogated some people in connection with the blasts, Sharma said. The group that claimed responsibility for the blasts warned of more such attacks in a text message to a television channel, the Press Trust of India reported, saying ISF-IM stands for Islamic Security Force-Indian Mujahideen.

The blasts follow ethnic clashes this month between indigenous groups and immigrants from neighboring Bangladesh in the tea- and oil-rich state. India has been hit by about 40 bombings in the past five months that have killed 175 people.

Rebel Groups

Assam, which also shares a border with Bhutan, is home to several rebel groups, including the United Liberation Front of Asom, or ULFA. At least 314 security personnel and civilians were killed last year in violence in the state.

President Pratibha Devisingh Patil and Prime Minister Manmohan Singh condemned the attacks and vowed to track down those responsible.

``Such barbaric acts targeting innocent men, women and children only highlight the desperation and cowardice of those responsible,'' Singh said in a statement yesterday. ``We will take all possible steps to maintain peace and bring the perpetrators of such acts to justice.''

The prime minister is planning a visit to the state tomorrow, his office said.

Long-standing disputes over land between members of the Bodo tribe and Muslim settlers from Bangladesh turned violent this month when 57 people were killed in clashes, including 25 when police opened fire on protesters. The dispute began Oct. 3 in the Udalguri district and spread to other areas.

Yesterday's attacks hit Guwahati, Assam's main city, and the Barpeta, Bongaigaon and Kokrajhar districts, Sarma said.

Ethnic Violence

Assam has experienced ethnic violence since the early 1980s and authorities have also battled a ULFA-sponsored insurgency, according to Doordarshan, the government-run broadcaster1. The outlawed group denied any role in yesterday's blasts, the Press Trust of India reported, citing an e-mail statement signed by Aanjan Borthakur of the ULFA's central publicity unit.

Cities and towns across India have been targeted by terrorists this year, with devices strapped to bicycles, hidden under auditorium seats and left near market stalls. Blasts on Oct. 21 in Imphal, capital of the northeastern state of Manipur, left at least 17 people dead.

Yesterday's attacks came six weeks after five blasts in New Delhi killed 26 people, the worst terrorist attack since 56 died in explosions in the western city of Ahmedabad on July 26.

A group called the Indian Mujahideen has claimed responsibility for recent terrorist attacks in India, including explosions in Jaipur, Ahmedabad and New Delhi. The Jaipur blasts, which took place on May 13, killed at least 68 people.

To contact the reporters on this story: Bibhudatta Pradhan in New Delhi at bpradhan@bloomberg.net; Michael Heath in Sydney at mheath1@bloomberg.net

Last Updated: October 31, 2008 10:52 EDT