Image copyright Getty Images Image caption The explosion occurred at a power plant owned by the Indian government

At least 29 people have been killed and as many as 100 injured in a blast at a coal-fired power plant in north India's Uttar Pradesh state, officials say.

About 80 people have been rushed to the company hospital, the government-owned plant operator National Thermal Power Corporation (NTPC) Limited said.

A further 10 people with serious injuries were sent to other facilities.

NTPC said there had been an "sudden abnormal sound" and an escape of gases and steam before the explosion.

The firm has launched an investigation into the blast at the plant, based near the town of Unchahar.

State police chief, Anand Kumar, said in a video statement, that preliminary findings suggested ash had collected in the furnace below the boiler, which meant "pressure built up inside and led to the blast".

Image copyright Getty Images Image caption Up to 100 people were injured in the blast, state police say

Uttar Pradesh's chief minister, Yogi Adityanath, has sent his condolences to those affected, and said the families of those killed would receive compensation.

Work-place incidents are a common occurrence in India, where safety standards are poor amid lax regulations.