He also directed officials to keep up the heightened security at the airport, railway stations, bus stands and other vital installations, the sources said.
Vigil was intensified in many areas, including popular market places, in south Delhi, central Delhi and the VIP movement zone in Lutyens' Delhi, a police official said. The police chief appealed to the residents to remain vigilant about any suspicious person or thing and report immediately to the police. "Citizens' vigil against suspicious persons/objects/activities is vital to counter terrorism. Report anything amiss (on) phone No.100 or helpline 1090," Bassi tweeted.