Authorities on Sunday imposed curfew in Jammu and Kashmir's Kishtwar town due to escalated tensions following the arrest of three youths.Police arrested the three late Saturday night on charges of trying to violate the law and order in the town.Announcements from mosques on Sunday morning called on civilians to protest against the arrests.The three youths were recently released after they served their term of detention under the Public Safety Act (PSA)."They have been picked up for their anti-social activities," police said.The PSA is a law applicable in Jammu and Kashmir only under which a person can be detained without a judicial process. The detentions can only be challenged in the state high court.