Delhi Police's Special Cell is questioning some people, including a few Iranian nationals, in connection with the minor blast near the Israeli Embassy, official sources said on Saturday.
A team from the National Bomb Data Centre (NBDC) of the NSG visited the spot for post-blast analysis, a senior officer said, adding that the findings will be shared with the Delhi Police team investigating the case.
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.