(CNN) A huge open-pit coal mine has collapsed in eastern India, trapping at least 30 people and killing at least seven, police officials say.

Hari Lal Chouhan, Superintendent of Police in Godda, where the mine is located, said seven bodies have been pulled out of the debris so far. The exact number of those feared trapped is unknown.

He added that as many as 20 vehicles have been buried in the landslide.

The cause of the landslide is still being investigated.

Photos: Mine collapses in Jharkand, India Hide Caption 1 of 2 Photos: Mine collapses in Jharkand, India Hide Caption 2 of 2

Catastrophe struck the vast mine Thursday evening local time, but rescue teams were unable to start their operation straight away due to a lack of technology, according to police officials.

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