UN Secretary General Antonio Guterres expressed grief at the killing of Indian photo-journalist Danish Siddiqui in Afghanistan, with the UN mission in the war-torn country calling for an investigation into his killing as well as those of other reporters.

"The Secretary General grieves the journalists killed or indeed harassed anywhere in the world and the case of Danish Siddiqui is one such case," Farhan Haq, Deputy Spokesperson for the Secretary-General, said at the daily press briefing on Friday.