MOGADISHU, Sept. 19 (Xinhua) -- Unknown gunmen have murdered a Somali journalist in central Somali town of Galkayo in the latest attack targeting media workers in the Horn of Africa nation, union officials said on Wednesday.

The National Union of Somali Journalists (NUSOJ) said the 29-year-old Abdirizak Said Osman, a newscaster and reporter for Radio Voice of Peace was stabbed to death on Tuesday evening.

"We deplore the barbaric killing of Abdirizak Said Osman the Puntland authorities must chase and catch the killers and those who masterminded Abdirizak's killing and bring them to justice," NUSOJ secretary general Mohamed Ibrahim Moalimuu said in a statement issued in Mogadishu.

Moalimuu said unknown assailants stabbed Osman at least six times in the chest and back in Garsoor village. He died from his wounds on his way to the General Hospital of Galkayo, according to his colleagues at Radio Voice of Peace.

The motive of the killing is still unknown and no one has so far been arrested following the brutal act, though the police said they are investigating the matter.

"Many crimes against journalists were committed with impunity but this time we demand the criminals to be prosecuted in front of justice," said Mahir Jama Aden, NUSOJ chairman.

Osman becomes the second journalist to be killed in Somalia in this year, according to the union.

On July 26, Abdirizak Kasim Iimaan, a TV cameraman, was killed by a policeman at a checkpoint in Mogadishu but no suspect has been arrested.

Somalia remains one of the most dangerous places in the world for journalists with dozens having been killed, maimed or forced to leave the country.

The Committee to Protect Journalists has said about 30 journalists have been killed in Somalia from 2012 to date.