BUKAVU, Congo, July 31 (Reuters) - A soldier shot dead 12 people and injured nine others during a drunken rampage in eastern Democratic Republic of Congo on Thursday evening, regional authorities said.

Security services are conducting a search for the gunman in the city of Sange, 15 miles (24 km) from the Burundian border, rape porn where the shooting took place, the governor of South Kivu province, Theo Kasi, said in a statement.

President Felix Tshisekedi called the attack a heinous crime and offered his condolences to the victims' families.

Congo's vast army is widely seen as poorly trained and unprofessional, and its personnel are frequently accused of committing crimes against civilians.

Senior generals are under U.S. and EU sanctions for alleged abuses, and are accused by the United Nations of having supplied weapons to rebels and criminal gangs. (Reporting by Crispin Kyalangalilwa and Stanis Bujakera; writing by Hereward Holland; Editing by Kevin Liffey)