Watch: Red Fort blast: Inside the investigation so far

A powerful explosion near Delhi’s historic Red Fort has left 13 people dead and dozens injured. Investigators suspect an improvised explosive device was used in what’s being treated as a terror attack. The NIA has taken over the probe, while security has been tightened across the capital. Home Minister Amit Shah chaired a high-level meeting, and Prime Minister Modi vowed that the conspirators will not be spared. Here’s everything we know so far about the deadly Delhi blast.