Moscow (AFP) - Russia on Thursday said no sign of torture was found on the bodies of three Russian journalists killed during a reporting trip in the Central African Republic this week.

"According to information given to the Russian embassy in CAR, during a first examination local doctors found no sign of torture, only gunshot wounds," foreign ministry spokeswoman Maria Zakharova said.

Journalists Kirill Radchenko, Alexander Rastorguyev and Orkhan Dzhemal were killed in the strife-torn African country on Monday.

They were reporting on the so-called Wagner Group, a company that sends Russian mercenaries to hotspots such as Syria and Ukraine that has been described as Moscow's shadow army.

On Wednesday, CAR authorities said the Russians were shot dead at a roadblock by a nine-man group.

In a statement on national television, CAR government spokesman Ange Maxime Kazagui said the nine "wore headscarves" and did not speak in French or Sango, two languages that are nationally used in the CAR.

One of the journalists violently opposed the armed men, who wanted to steal their equipment, Kazagui said.

One of the three died instantly and the two others died of their wounds, he said.

These details come from their driver, who was wounded but survived, he added.

An investigation into the incident has been opened by CAR, Russian federal authorities and the UN peacekeeping mission, MINUSCA.

The killings took place north of the central town of Sibut, located on the main highway between Kaga Bandora and the capital Bangui, a MINUSCA source said, speaking on condition of anonymity.

A journalist who was investigating Wagner's activities in Syria in April died after falling from the balcony of his fifth-floor flat in the Russian city of Yekaterinburg.

But Kazagui said it was "very plausible" that the three journalists had been killed by "a roadblock team who belong to an armed group".

"They took risks that, in my view, were badly underestimated."