The SPG is believed to have advised Modi, who is the main campaigner for the ruling BJP, to cut down on road shows, which invite a bigger threat, in the run-up to the 2019 Lok Sabha polls, and instead address public rallies, which are easier to manage, an official said.

The close protection team (CPT) of the prime minister's security has been briefed about the new set of rules and the threat assessment and instructed them to frisk even a minister or an officer, if necessary.

The prime minister's security apparatus was reviewed threadbare recently after the Pune Police told a court on June 7 that they had seized a "letter" from the Delhi residence of one of the five people arrested for having alleged "links" with the banned CPI (Maoist), another official said.

The purported letter allegedly mentioned a plan to "assassinate" Modi in "another Rajiv Gandhi-type incident", the police had told the court.

Besides, during a recent visit to West Bengal, a man was able to break through six layers of security to touch the prime minister's feet, sending the security agencies into a tizzy.

Following the two developments, Home Minister Rajnath Singh held a meeting with National Security Advisor Ajit Doval, Union Home Secretary Rajiv Gauba and Director Intelligence Bureau Rajiv to review the prime minister's security in the wake of inputs about threat to the Prime Minister's life.

In that meeting, the home minister had directed that all necessary measures be taken in consultation with other agencies to suitably strengthen security arrangements for the prime minister.

Maoist-hit states like Chhattisgarh, Jharkhand, Madhya Pradesh, Odisha, West Bengal were termed as sensitive by the Home ministry and the police chiefs of these states were told to be extra careful when the prime minister visits their states, the official said.

Security agencies are believed to be specially monitoring the Kerala-based Popular Front of India (PFI), an outfit that the government believes is a front for radical groups.