MUMBAI - POLICE were on Tuesday investigating twin blasts overnight that killed eight people and injured nearly 100 in two areas of western India wracked by Hindu-Muslim tensions, officials said.

Seven people were killed and 82 injured in an explosion near a mosque in the town of Malegaon, 175 miles (280 kilometres) from India's financial hub, Mumbai, police said.

But it was unclear what caused the blast, amid reports that gas cylinders may have exploded accidentally.

'It is not yet clear what caused the blast. All I can say at this point is that an investigation is on,' additional district magistrate Ramesh Kale said by telephone.

Rioting and stone-throwing broke out after the blast, forcing police to fire shots in the air to control angry crowds in the predominantly Muslim town.

Five police officers were injured and a curfew was put in place, police said.

'Right now the situation is peaceful, totally under control,' Mr Kale said.

The head of Mumbai's anti-terrorism squad, Mr Hemant Karkare, said a team of investigators was heading to Malegaon, according to the Press Trust of India news agency.

Separately, a 15-year-old Muslim boy was killed and nine others wounded in a blast in a crowded market in a Muslim part of Modasa town in neighbouring Gujarat state, district magistrate M. Thennarasan said.

Earlier, Gujarat's Home Minister Amit Shah told NDTV that the device was planted on a motorcycle.

'We are reviewing security arrangements,' Mr Shah said.

The explosions late on Monday came after a wave of attacks in Indian cities claimed by an Islamic militant outfit called the Indian Mujahideen, seemingly directed at middle-class Hindus.

Malegaon was hit by simultaneous bomb blasts in September 2006 which killed 38 people and wounded more than 100. Most of the victims were Muslims.

Gujarat state, ruled by the Hindu nationalist opposition, is considered particularly sensitive because it was the scene of serious rioting in 2002, when an estimated 2,000 people - mostly Muslims - were killed by Hindu mobs.

Gujarat's commercial capital Ahmedabad was hit by a string of 16 bombs in July this year that killed 45 and injured more than 160.

Police in Ahmedabad announced earlier Monday they had found 17 'crude explosive devices' dumped in rubbish.

Several other Indian cities - Jaipur, Bangalore and New Delhi - have been hit by serial bombings since May.

The latest was last Saturday, when a bomb attack on a crowded market in New Delhi killed two people and wounded 22. -- AFP