New Delhi: Delhi has been put on high alert following intelligence inputs indicating a possible terror threat, forcing Delhi Police and other security agencies to increase surveillance at several sensitive locations.“Police have been directed to keep a strict vigil on suspicious activities, abandoned objects and vehicles parked in sensitive areas,” PTI quoted an officer as saying.According to officials, security agencies have received alerts about possible attempts to target key offices and crowded areas in central Delhi through suicide attacks, vehicle-borne improvised explosive devices (IEDs), firing and coordinated attacks.Security has been tightened around the ruling Bharatiya Janata Party (BJP) headquarters and nearby government establishments on Deen Dayal Upadhyay (DDU) Marg, with additional deployment of armed personnel, barricading and increased checking of vehicles.Also read: Delhi Police arrests suspects linked to criminal gangs in India, PakistanAnti-sabotage inspections are underway at major government buildings, political offices, markets, transport hubs and other crowded places across the city.Bomb disposal squads, sniffer dog units and quick response teams along with the Delhi Fire Service have also been put on alert.Security measures have been additionally strengthened in settlements and areas considered sensitive from a law and order perspective, while local police are carrying out random checking operations and verification exercises.Senior officials are closely monitoring the situation and reviewing the security arrangements across the city.On November 10 last year, at least 15 people were killed and more than 20 were injured in a blast inside a car near the Red Fort. The incident is the first terrorist attack in the national capital since 2011.