Qatar's interior ministry says an explosion resulting from a "technical accident" has occurred at a factory in Ras Laffan, an industrial city north of the capital Doha and site of the country's core LNG processing operations.

It said several injuries were reported but no leak that "threatens safety".

The ministry did not give the exact location of the explosion but a source with knowledge of the matter said it occurred at the Barzan gas plant in Ras Laffan and was due to an "operational error".

A Reuters witness had said a loud boom was heard in Doha.