A woman has been arrested in Somalia's capital after she alleged in a video interview posted online that she had been raped at gunpoint by colleagues.

The journalist who interviewed the 19-year-old has also been detained in Mogadishu, but the two men accused of rape have not been arrested.

Earlier this year, another alleged rape victim and the reporter she had spoken to were sentenced to a year in prison for "offending state institutions".

The UN has called for a "proper investigation" into the current case.

Somalia's UN-backed government said it could not get involved in the judicial process and justice must take its course.

The alleged victim is herself a journalist who works for the Kasmo Voice of Women radio station in Mogadishu.

Fatuma Abdulkadir Hassan told a journalist at the privately owned Shabelle Media Network that she had been raped at gunpoint by colleagues who worked at the state-owned radio station.

One of the journalists contacted her by phone and asked if she could help him without making it clear how - and a car was sent to her house to collect her, she said.

She alleges it dropped her off at a house where she found the two journalists.

"One of the men threatened me with a pistol, and took me to the bedroom by force... both of them raped me several times, destroying my pride and dignity," she said in the interview with the journalist, which was videoed and posted online by Shabelle and has since been picked up by several Somali news websites .

Police arrested Ms Hassan, the Shabelle journalist Mohamed Bashir Hashi who conducted the interview, and the manager of Shabelle.

The manager has since been released on bail; the other two remain in custody.

Human rights groups say rape and sexual abuse is a growing problem in Somalia where more than two decades of conflict have seen clan-based warlords, rival politicians and Islamist militants’ battle for control of the country.