Birbhum (West Bengal), April 21, At least seven people were killed and several others injured in a crude bomb explosion in West Bengal's Birhum district on Friday, police said.

"There was a clash between two groups of miscreants in Birbhum's Labpur. They hurled bombs at each other... At least seven people of the rival groups died in the explosion. The death toll may increase," Birbhum Superintendent of Police N. Sudheer Kumar told IANS.

The situation had been tense in the area since Friday morning as the two groups clashed with each other with arms.

Bombs were hurled at several places in the village, including school premises, causing panic among students and villagers.

"We had an examination scheduled in the school, but the students were not able to come out of their homes owing to the violence since morning. So, we had to postpone the examination," the headmaster of a local high school said.

According to police, the clash between the two groups was an offshoot of war for supremacy in the area.

"The people who died in the explosion were involved in making crude bombs. Bomb-making materials like stone chips and explosives have been recovered from some of the deceased's house," the officer said.

The local Left Front units accused the Trinamool Congress activists of factional fight in the area over the possession of sand mining.

Refuting those allegations, the local Trinamool leadership accused the Left Front-backed miscreants for the chaos in the region.

"I have heard the news. There is no factional fight in the local Trinamool units. The violence is perpetrated by CPI-M backed miscreants," district Trinamool Congress President Anubrata Mondal alleged.