hubaneswar, Jan 2 (PTI) Amidst tight security, hundreds of tribals from across Odisha today observed 'Martyr Day' marking the killing of 13 adivasis at Kalinga Nagar in Jajpur district during construction of the boundary wall of an industry on January 2, 2006. The tribals under the banner of Bisthapan Birodhi Jana Mancha (BBJM) held a rally before holding a meeting addressed by different anti-displacement leaders. The 13 tribals were gunned down by the police while opposing construction of the boundary wall of a private steel company at Kalinga Nagar. One police person was also killed in the attack by tribals in the incident which took place six years ago. Describing the 2006 incident as "tragic", Chief Minister Naveen Patnaik said that his government believed in peaceful industrialisation in the state. "The innocent tribals were brutally killed by the police as they opposed forceful land acquisition by the state government. Though six years have passed since the incident, the tribals are yet to overcome the shock," said noted anti- displacement leader Prafulla Samantray who addressed the meeting.