Tirupati: Police stepped up surveillance and conducted extensive searches through bomb and dog squads at prominent temples, guest houses, bus stands, railway stations, judges’ quarters and other prominent locations in Tirupati on Friday following bomb threat alerts received at several states in the country. Tirupati SP L Subbarayudu said the searches were being carried out as a precautionary measure and appealed to the public to reach out if they came across any suspicious activity in their neighbourhood. Frisking at high pilgrim congregation points as well as VIP commute routes in the city has also been intensified.