New Delhi, May 9 -- The Bureau of Civil Aviation Security (BCAS) issued a detailed advisory on Thursday mandating stricter security protocols at airports nationwide amid escalating tensions with Pakistan. Following the advisory, airlines issued messages of their own and warned passengers to arrive at airports at least three hours before departure. Akasa Air, IndiGo and SpiceJet all issued advisories urging travellers to allow extra time for additional security checks. Check-in counters will close 75 minutes before flight time, added Air India. The new security measures, effective until May 18, bar visitors from entering airport buildings and suspend the sale of visitor tickets. Additional passenger and baggage checks will be conducted at boarding gates for all flights, on top of the regular security screenings. "In view of the recent attack in Pahalgam and subsequent surcharged security scenario, it is necessary to enhance security measures at all airports and aviation facilities so that no untoward incident takes place in the country," the BCAS advisory said. At least 24 airports across northern India remain closed until at least Saturday morning, with Delhi and Dehradun now serving as the only operational northernmost airports in the country. The closures have led to widespread flight cancellations. The BCAS ordered a comprehensive review of security processes, including checks of passenger lists, cargo manifests, and aircraft catering services....