New Delhi, Jun 17 (IANS): The National Investigation Agency (NIA) has taken over the investigation into a series of attacks carried out by Khalistani elements in Indian missions in the US and Canada, Delhi Police sources told IANS on Saturday.

The Delhi Police Special Cell had previously registered two FIRs under the Unlawful Activities (Prevention) Act (UAPA) regarding the attacks that took place in March in San Francisco and Toronto in March.

Following a careful examination of the case, the police decided to transfer the investigation to the NIA, given their expertise in dealing with cases involving terrorism and transnational elements, the sources said.

In recent times, there have been instances of pro-Khalistan supporters in the US issuing threats towards New Delhi's Ambassador to Washington, Taranjit Singh Sandhu, during their protests.

On March 20, multiple videos captured a large mob launching an attack on the Indian Consulate in San Francisco, while loud Punjabi music played in the background.

The assailants had vandalised the outer wall of the building by spray-painting a prominent graffiti that read "Free Amritpal", referring to the jailed Waris De chief Amritpal Singh.

The attackers used the wooden butts of Khalistan flags, which they had been waving earlier, to smash the glass doors and windows of the Consulate.

Despite the mob breaching a barricade, they could not enter the Consulate premises.

Also in March, pro-Khalistan supporters organised a protest outside the Consulate General of India in Toronto during which they reportedly engaged in acts of aggression towards Indian-origin journalists who were present at the scene.

In response, the External Affairs Ministry had lodged a "strong concern about the actions of separatist and extremist elements" and also "sought an explanation on how such elements were allowed, in the presence of police, to breach the security of our diplomatic Mission and Consulates".