In Assam, security has been tightened in vulnerable areas of Chirang district after one person has died in grenade blast at Basugaon of the district last evening. Three persons were injured in the blast. Security forces have already launched search operation to nab the culprits. One live grenade was also recovered from the spot. It may be recalled that thousands of people displaced due to the ethnic clashes recently in Chirang along with a few neighbouring districts. Meanwhile, day curfew has been relaxed at Dhubri police station area in Dhubri district from 5 AM today. Administration has clamped night curfew yesterday (5 pm to 5 am) after local people demanded arrest of the miscreants who attacked and injured a youth on Tuesday night. A strict vigil is being maintained by security forces.