A campaign was launched against Indian Prime Minister Narendra Modi on Twitter after reports surfaced that the premier was following accounts on the social media platform that celebrated the murder of Indian journalist Gauri Lankesh, reported Al Jazeera.

Lankesh, a known critic of right-wing groups and Sangh organisations, was killed last week when assailants opened fire at her as she arrived at her Bangalore home. Lankesh had recently been found responsible in a defamation case by a lawmaker of India's ruling Bharatiya Janata Party (BJP) for her writings on Hindu nationalists.

The Twitter campaign against Modi uses the hashtag #BlockNarendraModi, which trended on the social media platform on Wednesday and Thursday in India, Al Jazeera said. The campaign calls for Modi to unfollow the Twitter accounts that hailed the murder of the journalist.

Among the Twitter handles followed by Modi is Nikhil Dadhich, a self-acclaimed Hindu nationalist, Hindustan Times reported.

In a post that has now been deleted, Dadhich had levelled obscenities against Lankesh and said that she deserved to have died, the Indian daily said.

Following the criticism of the prime minister, Amit Malviya, the BJP's national head for information and technology, made a statement in defence of the prime minister, Hindustan Times reported.

"PM following someone is not a character certificate of the person, and is not in any way a guarantee of how the person would conduct himself," the daily quoted Malviya as saying.

The murder of Lankesh sparked outcry in India last week as activists, politicians and journalists demanded a full investigation into the incident.

The Editors Guild of India said her death was “an ominous portent for dissent in democracy and a brutal assault on the freedom of the press”, calling for a swift and thorough investigation.

According to Al Jazeera, Modi has not condemned the murder of Lankesh.