Israel on Tuesday night issued an advisory urging its nationals living in India, especially Delhi, to be extra vigilant after a low-intensity explosion near the Israeli embassy on Dr A.P.J. Abdul Kalam Road in the national capital earlier in the evening.

Stating that “it is possible that this is an attack”, Israel’s National Security Headquarters in Tel Aviv said that “in light of the fear of a recurrence of the events”, Israelis should avoid crowded places including malls and markets known to be frequented by westerners and Jews and be extra-vigilant in public.

The advisory also asked Israelis to desist from “externalising Israeli symbols”, stay away from events that are not secured and have many participants, and refrain from posting travel details and photographs on social networks.

On Wednesday, Delhi police said it had identified two persons who were caught on camera walking on the road close to the spot shortly before the low-intensity explosion at the rear side of the embassy. No one was injured in the blast.

“The probe into the cause of the blast is still underway,” said a senior Delhi police officer.

The preliminary probe had earlier suggested an explosion akin to a “cracker blast” in an empty plot a few metres from the embassy on Tuesday around 5.20pm. The police on Wednesday said the possibility of a “chemical explosion” cannot be ruled out since no remnants of the explosive were found at the spot.

A Delhi police officer said an “abusive” one-page threat letter addressed to the Israeli ambassador was found near the spot. The letter and other exhibits lifted from the spot have been sent for forensic examination.

Investigators are scanning “end-to-end encrypted calls” of active mobile phone numbers near the Israeli embassy at the time of the incident as part of its probe.

“We are probing it from all angles. Special teams are checking the registration numbers of all vehicles that passed the area around the time of the blast and prior to the blast. We are scanning multiple CCTVs in and around the area,” the police officer said.

The police said security had been intensified in areas around the Israeli embassy and Jewish establishments in the capital. Even prior to the blast, security had been beefed up around the highly secured mission after Israel began bombing Gaza in the wake of the terror strike by Hamas on October 7.

Police sources said Tuesday’s blast was very similar to the 2021 low-intensity explosion that occurred outside the Israeli embassy in which no one was injured. The police had found a letter addressed to the Israeli ambassador then also. The National Investigation Agency (NIA) is still probing the case and has failed to make any breakthrough so far.