The minor blast took place on Friday evening in a high-security zone of the national capital. No one was injured.
An envelope addressed to the Israeli Embassy and containing a note was found at the site of the blast, sources had said. It had reportedly suggest an Iranian link to the incident.
Earlier in the day, an investigation team of Delhi Police’s Special Cell visited the site near the embassy to collect more evidence as part of its ongoing probe.
A case has been registered and the Special Cell is investigating the matter.