Bengaluru, June 16 : After a gap of 112 days, Karnataka reported more than 600 fresh Covid-19 cases, triggering concerns among health authorities in the state. In the last 24 hours, 648 cases were registered and one fatality, the second this month after a previous death was reported on June 5. Bengaluru reported the highest cases at 615, which increased the state capital's active caseload to 3,843. Dakshina Kannada district, which shares a border with Kerala state, reported 12 fresh cases. Meanwhile, there were no cases from Bagalkot, Bidar, Chamarajanagar, Chikkaballapura, Chikkamagaluru, Chitradurga, Davanagere, Gadag, Haveri, Kodagu, Koppala, Mandya, Raichuru, Ramanagar, Udupi, Vijayapura and Yadgir districts. The state's health department has published operational guidelines for revised surveillance strategy in the backdrop of the steady Covid spike. Health Minister K. Sudhakar stated that surveillance officers have been directed to initiate strict measures with regards to international arrivals, genomic sequencing, sero-survey, among other factors. Also in the last 24 hours, 23,452 Covid tests were conducted across Karnataka. The state's positivity rate stood at 2.76 per cent and the number of active cases increased to 3,997 cases. Thirty people are currently hospitalised. /IANS