Senior journalist-activist and a strident critic of Hindutva politics, Gauri Lankesh was shot dead by unidentified assailants just outside her residence in southern Indian city of Bengaluru on Tuesday night.

Gauri, 55, editor of a Kannada language tabloid “Gauri Lankesh Patrike”, on returning home by her car was opening the gate when the assailants riding a motorcycle opened fire on her indiscriminately from close range. Two bullets hit her on the chest and forehead, police officials said, adding she died instantaneously.

Four bullets hit the compound wall of her building in Rajarajeshwari Nagar, the officials said.

Gauri, who owned some other publications, was known for her forthright views against hardline Hindutva politics and pro-Left leaning.

Bengaluru Police Commissioner T Sunil Kumar could not immediately ascertain who carried out the killing and the motive behind it.

Police suspected that she had been closely followed by the assailants.

Karnataka Chief Minister and senior Congress leader Siddaramaiah termed the killing shocking and said three police teams had been constituted to probe the incident. Instructions had been issued to crack the case and bring the culprits to book at the earliest.

Recently, Gauri had been instrumental in bringing Naxalites into the mainstream and they had surrendered, he said, adding, "It's shocking news for me. No one who has faith in humanity will ever kill anyone. Gauri Lankesh was secular and helped government bring the Naxals back to the mainstream.”

He wondered why Gauri had not told him about the threat to her life though she met him many times.

Karnataka Home Minister Ramalinga Reddy drew parallels between the gunning down of Gauri and rationalists Narendra Dabholkar and M M Kalburgi, allegedly by fringe Hindu groups.

Dabholkar was shot dead in August 2013, in Kolhapur, Maharashtra while Kalburgi was gunned down in Karnataka in August 2015.

"Who is behind the incident? Is it the Naxals or any other ideological fringe parties will be known only after investigation,” Reddy said.

Siddaramaiah also said he had asked police to get in touch with their Maharashtra counterparts while probing the murder of Dabholkar.

Karnataka police chief R K Dutta said Gauri had not expressed apprehension about any threat to her life during a couple of meetings he had with her.

"I do not know how to react. The assailants should be brought to book. The case should be handed over to CBI," Gauri's brother Indrajit Lankesh said.

In a statement, RSS Karnataka unit expressed deep sorrow over the "heinous" murder of Gauri. "RSS appeals to the state government to act soon on the criminals responsible and bring them to book," it said.

Veteran BJP Leader K S Eshwarappa rapped the Siddaramaiah government for "failing" to protect the lives of people, including those of noted writers like Kalburgi and Gauri.

Gauri was last year convicted in a defamation case filed by BJP lawmaker Prahlad Joshi over a report published in her tabloid against some leaders of the party.

India's Minister of State for Information and Broadcasting Rajyavardhan Rathore took to Twitter to denounce the incident.

"Terrible news from Bengaluru about the heinous murder of Gauri Lankesh. I condemn all acts of violence against journalists," he said.

Congress Vice President Rahul Gandhi said, "Truth cannot be silenced". He demanded that the culprits be tracked down and punished.

"Gauri Lankesh lives on in our hearts. My condolences and love to her family. The culprits have to be punished," his office said in a twitter post.

BJP National General Secretary P Muralidhar Rao said, "The murder of #GauriLankesh is condemnable outright. Onus is on Sh.Siddaramaiah to ensure proper investigation."

Gauri was a journalist-activist, known for her anti-establishment, pro-poor and pro-Dalit stances.

Among very few women editors in Kannada journalism, she was a fierce activist, who openly expressed her pro-Naxal and Leftist views.

Born in 1962, Gauri was the daughter of noted Kannada journalist and founding editor of Kannada weekly tabloid “Lankesh Patrike”.