Police in India are investigating a series of explosions which killed three people and injured more than 50 others in the southern state of Kerala. The blasts took place during an event by Jehovah"s Witnesses, a Christian-based religious movement, in the town of Kalamassery on Sunday. A man was detained after he posted a video claiming responsibility for the attacks and surrendered to police. Police said they were still trying to verify his confession. "He is in our custody but we have not recorded his arrest so far. We are still trying to ascertain the veracity of his statement, it will take some time," Kerala police"s public relations officer Pramod Kumar told Reuters. The incident took place during a prayer session organised by Jehovah"s Witnesses in Kalamassery. More than 2,000 followers were attending the three-day event. Two people died on Sunday, while a 12-year-old girl with 95% burns succumbed to her injuries on Monday morning. Senior police official Shaik Darvesh Saheb said a preliminary investigation indicated that an improvised explosive device (IED) placed inside a tiffin box might have caused the blasts. Shortly after the incident, a man named Dominic Martin said he had carried out the attack. The 48-year-old posted his confession in a Facebook video, which has since been deleted, and handed himself in at a nearby police station. Martin claimed he was a registered member of the religious group and was angry with its "anti-national" teachings. But TA Sreekumar, a regional spokesperson for the Jenovah"s Witnesses, has denied this and told Reuters that he was unaware if Martin was even present at the event. On Monday, Kerala Health Minister Veena George told reporters that 17 people had been admitted to different hospitals, 12 of whom were in intensive care. "Four are critically ill, three of them are on ventilators. Those who are critically ill have burns above 50-60%," she said. Chief Minister Pinarayi Vijayan condemned the incident and announced that a 20-member team, led by the assistant director general of police, was investigating the incident. He also said that he would hold an an all-party meeting on Monday to discuss the blasts. Meanwhile, security has been tightened in India"s capital Delhi and other cities like Mumbai in the wake of the blasts. — BBC