A South African security trainer has been killed in Somalia by unknown gunmen during a government-approved mission against pirates, the government of the semi-autonomous region of Puntland said.Pirates operating from the Somali coast have raked in millions of dollars in ransoms from hijacked ships, including oil tankers in the Gulf of Aden and the Indian Ocean, in what costs the world economy billions of dollars a year.The security officer was killed on Friday while on a mission targeting pirates in a coastal area used by pirates as a base and where hijacked ships have been held for ransom, Puntland said in a statement late on Saturday.Officials at Saracen International, the security firm where he worked, were not immediately available to comment.South Africa’s international relations department said it had been informed of the death. "We have received reports of the incident and the mission is looking into it,” said foreign ministry spokesman Clayson Monyela.Puntland has been relatively stable compared to other parts of the country which has lacked effective central government for two decades.Somalia’s al Qaeda-linked militants did not claim responsibility directly for the latest killing but urged further attacks against foreigners."I urge clans and fighters to redouble their efforts of killing our enemies,” Sheikh Ali Mohamud Rage, the spokesman for al Shabaab, told Reuters.