A United Nations envoy has condemned the killing of two prominent journalists in Somalia.
Mahad Ahmed Elmi was shot dead on his way to work
Eric Laroche, the UN Humanitarian Co-ordinator for Somalia, urged the authorities to conduct a prompt and impartial investigation.
Mr Laroche said freedom of expression remained "vulnerable" in Somalia.
HornAfrik radio owner, Ali Iman Sharmake and station presenter, Mahad Ahmed Elmi, died in separate attacks in Mogadishu on Saturday.
The Somali transitional government says the military have arrested two men over the killings.
Mr Laroche, quoted by the AFP news agency, urged all authorities and groups "to respect the right of all to hold opinions without interference and to seek, receive and impart information through any media".
He went on: "The violent events of the last days show how vulnerable freedom of expression remains in Somalia.
"The transitional federal government is responsible for ending impunity for attacks on journalists by conducting prompt and impartial investigations and preventing any form of harassment of the media."
Mr Sharmake died when his car exploded after apparently running over a landmine. He had just been to the funeral of Mr Elmi who was shot dead hours earlier.
HornAfrik - which also relays BBC Somali service programmes - prides itself on its journalistic independence, and its broadcasts have in the past angered both the government and Islamist opposition.
A number of local and foreign journalists have been killed in recent years.
Mogadishu has been the scene for months of skirmishes between troops supporting the transitional government and both clan-based and Islamist insurgents.