The death toll in the blast near Red Fort rose to 12 on Tuesday, with three more people succumbing to injuries, police said.
A powerful explosion had ripped through a slow-moving car at a traffic signal near the Red Fort metro station on Monday evening. Till Monday night, nine people were confirmed dead and 20 others injured, officials said.
Police confirmed that three more people succumbed to their injuries, taking the toll to 12.
Delhi Police on Tuesday registered an FIR under the Unlawful Activities (Prevention) Act and the Explosives Act in connection with the deadly blast.
Raids are being conducted at multiple locations, and the national capital has been placed on high alert, with strict vigil being maintained at airports, railway stations, and bus terminals.