A BBC news team, including Moscow correspondent Steve Rosenberg, has been attacked and their recordings wiped as they filmed in southern Russia.

The corporation has now lodged a formal complaint with Russian authorities.

It has called for a thorough investigation into the incident in which it said the crew were "badly beaten".

Mr Rosenberg was accompanied by a producer and cameraman, who have not been named, all from the Russian bureau.

The BBC said that although the men are okay, the cameraman is still receiving treatment for concussion and other injuries.

At the time of the attack, Mr Rosenberg and his team were investigating reports of Russian servicemen being killed near the border with Ukraine.

The BBC said today: "We deplore this act of violence against our journalists and call on the Russian authorities to conduct a thorough investigation and to condemn the assault on our staff."

In a statement the corporation said: "After filming in the city of Astrakhan, our team was assaulted by unidentified men in a co-ordinated attack.

"Our staff were badly beaten, their camera destroyed and then taken.

"After alerting the emergency services, the team was then taken to a police station for four hours of questioning after which they discovered that recording equipment - which was in their vehicle, at the police station - had been electronically wiped.

"The attack on our staff, and the destruction of their equipment and recordings, were clearly part of a co-ordinated attempt to stop accredited news journalists reporting a legitimate news story."

The BBC said it would be making "no further comment" about the incident.