The blast takes place as hundreds gather for Sunday prayer in the southern town of Kalamassery in Kerala state.
The blast took place as hundreds of followers of the Jehovah’s Witnesses denomination gathered for prayer on Sunday morning at a convention centre in Kalamassery town.
“At about 9:40am [04:10 GMT], there was an explosion in Zamra International Convention Centre in which one person died and 36 are undergoing treatment,” Kerala’s Director General of Police Darvesh Saheb told reporters.
“We will find out who is behind this and take stringent action … preliminary investigation shows it was an IED [improvised explosive device] blast,” he said.
Videos filmed shortly after the explosion and posted online showed flames inside the building and rescuers helping people clear out.
“We are examining all angles and will find out who is behind this,” Saheb added.
Jehovah’s Witnesses is a sect of Christianity known for its worldwide practice of door-to-door evangelism. The movement teaches non-violence and stays politically neutral, with members refusing to vote or serve in the military.
India, with a population of 1.4 billion, has only about 60,000 Jehovah’s Witnesses followers, its adherents say. There are about 28 million Christians in India, as per the 2011 census.
A section of local media reported that there were three separate blasts at the prayer gathering, each hitting different areas of the convention hall.
“The explosions occurred seconds after the end of a prayer as part of the day’s event. The first blast took place in the middle of the hall. Seconds later, two more explosions rocked simultaneously on either side of the hall,” TA Sreekumar, regional spokesperson for the Jehovah’s Witnesses, told mathrubhumi.com.
Jehovah’s Witnesses, founded in the United States in the 1870s, has frequently been the victim of persecution around the world.
In Russia, the movement has been branded as an “extremist” group despite its pacifist views and hundreds of its followers have been arrested in recent years.
In March, an armed man killed seven people in Hamburg, Germany at a Jehovah’s Witnesses prayer hall.