Ulfa blast kills 4 in Assam

At least four people have been killed in a bomb blast at a crowded market in the north-eastern Indian state of Assam, police say.

Fifty others were wounded in the explosion at Kumarikata in the west of the state near the border with Bhutan.

Police blamed the attack on separatist rebels belonging to the United Liberation Front of Assam (Ulfa).

They said the bomb was in response to a truce announced by some Ulfa commanders which the group's top leaders oppose.

"The bombs exploded when there were hundreds of villagers in the market. This is a serious attack and a very heinous one," said Assam Chief Minister Tarun Gogoi.

The BBC's Subir Bhaumik in Calcutta says a number of the wounded have been taken for treatment to the Assam state capital, Guwahati.

Assam police intelligence chief Khagen Sharmah told the BBC the explosion was a "direct reaction" to the ceasefire declaration by some Ulfa commanders.

"There is no doubt that such a powerful explosion can be done by only one group in Assam and that is the Ulfa," he said.

Ulfa has not said it carried out the bombing or denied it.

The group began an armed rebellion against what it describes as colonial rule by Delhi in 1979. Thousands of people have died in the violence.

An effort to start peace talks between the rebels and the Indian government broke down in 2006.

The rebels are seeking a separate homeland for the Assamese people and demanding the departure of the non-indigenous population, particularly Hindi speakers.

Earlier in June, some Ulfa commanders started secret negotiations with the Assam government and the Indian army, following which they announced a ceasefire.

Top Ulfa leaders say they have fallen into a "government trap". ]