JOHANNESBURG (Reuters) - Former South African President Nelson Mandela, who has been in hospital for a week with a lung infection, has successfully undergone a procedure to have gall stones removed, the government said on Saturday.

"The former president underwent a procedure via endoscopy to have the gall stones removed ... The procedure was successful and Madiba is recovering," the government statement said.

(Reporting by Agnieszka Flak; Editing by Andrew Heavens)