World War One Diary for Thursday, December 21, 1916:

Eastern Front

Western Russia: Fighting south of Dvinsk.

Dobruja: Sakharov drives Bulgars into Lake Babadagh south of Tulcea.

Middle East

Sinai: Anzac Mounted Division occupies El Arish (1,600 Turks evacuated to Magdhaba on December 20). Royal Navy N arrives on December 22.

Sea War

North Sea: Royal Navy destroyer Negro sunk by collision with flotilla leader Hoste.

Neutrals

Greece: Allied note demands control of communications and Venizelists‘ release. Similar conditions demanded on December 31 before blockade lifted.