Afghanistan's highest court has ruled that a police officer convicted of murdering Associated Press photographer Anja Niedringhaus and wounding an AP correspondent almost one year ago should serve 20 years in prison.

Documents sent to the country's attorney general on Saturday reduce the final sentence for former Afghan police unit commander Naqibullah — who was originally sentenced to death last year.

Naqibullah, who uses only one name, opened fire on Niedringhaus and Kathy Gannon without warning as they were covering Afghanistan's presidential election outside the southeastern city of Khost in April.

An award-winning German photographer, Niedringhaus was renowned for her humane depictions of ordinary life as well as for her coverage of conflict zones.