NEW DELHI (AFP, Reuters, Bernama) - A senior Indian journalist was shot dead by unidentified attackers in southern Karnataka state, its chief minister said on Tuesday (Sept 5), confirming the country as Asia's deadliest for reporters.

"Absolutely shocked to learn about the murder of renowned journalist Gauri Lankesh. I have no words to condemn this heinous crime," chief minister Siddaramaiah said on Twitter late Tuesday.

Lankesh, who edited an Indian weekly newspaper, was an outspoken critic of right-wing Hindu nationalist politics.

Last year, she was convicted of criminal defamation for one of her articles on local Bharatiya Janata Party (BJP) leaders. She was appealing against the verdict, a BBC report said.

While the motivation for the killing was not immediately clear, political leaders, journalists and activists took to Twitter to express their outrage and denounce intolerance and any threat to free speech.

A Press Trust of India (PTI) report said that Lankesh was opening the entry gate to her residence when she was shot dead by the "motorcycle-borne assailants" in the state capital Bangalore.

The report said that Lankesh, 55, died "instantaneously" after two bullets hit her chest and one her forehead.

Her body was found lying in a pool of blood outside her home.

"I have spoken with the DGP (Director General of Police), and instructed him to ensure prompt and thorough investigation to bring the perpetrators to justice," Siddaramaiah said on Twitter.

"People in front of her house heard gunshots," the city's police commissioner, T. Suneel Kumar, told reporters. "We found four empty cartridges from the scene."

India's otherwise progressive southern state has seen some targeted killings of political activists and scholars in the recent past.

In 2015, India was rated as the deadliest country in Asia for journalists by Paris-based Reporters Without Borders.