* North Caucasus is riven by Islamist insurgency
* Putin urges those responsible for killing to be caught (Adds comments from Putin)
By Gabriela Baczynska
MOSCOW, Dec 6 (Reuters) - A state television presenter in Russia's volatile North Caucasus was shot dead late on Wednesday, a killing federal investigators said may have been meant as a warning to journalists reporting on an Islamist insurgency.
Kazbek Gekkiyev, 28, who worked for a local channel of Russian state broadcaster VGTRK, was killed in Nalchik, capital of the internal republic of Kabardino-Balkaria, the federal Investigative Committee said.
He was not known for reporting on crime or the insurgency, which is less prevalent in Kabardino-Balkaria than in other areas nearby such as Dagestan.
A woman identified as a witness by another VGTRK channel said two people had got out of a car and asked Gekkiyev, 'Are you TV presenter Kazbek Gekkiyev?' before the shots were fired.
Colleagues were reported as saying they did not understand the motive for the killing, and the investigators said they were not ruling out any possible cause.
President Vladimir Putin urged security forces to find those responsible for the killing.
"All people must be protected ... and I am sure that our law enforcement bodies will do everything so that the criminals will be revealed and punished," he told reporters in the city of Sochi, a few hundred kilometres away from Nalchik.
The Organisation for Security and Cooperation in Europe said last year that the North Caucasus, a mostly Muslim area in southern Russia, was one of the most dangerous places in the world for journalists.
Local representatives of federal bodies, especially the Interior Ministry, are often targets of violence there.
Media cited Gekkiyev's co-workers as saying that other presenters at the station were taken off the air after receiving threats from local insurgent leaders.
The reports said those journalists had reported on operations by security forces against Islamist radicals.
Vladimir Markin, a spokesman for the Investigative Committee, said the security services were still trying to identify suspects.
But he said investigators suspected Gekkiyev was killed as "a threat to other journalists speaking about results of the fight against the bandit underground in the republic".
Authorities often refer to insurgents as members of the "bandit underground".
The insurgents, who wage nearly daily violence across the North Caucasus, say they want to create an Islamic state in the area wedged between the Black and Caspian Seas.
Ethnic tension, including those between Balkars and Kabardins in Kabardino-Balkaria, helps drive the insurgency, along with grievances stemming from corruption and strong-arm police tactics used by local leaders to staunch the violence. (Editing by Tom Pfeiffer and Andrew Osborn)