The Caucasus campaign comprised armed conflicts between the Russian Empire and the Ottoman Empire, later including Armenia, Azerbaijan, Georgia, the Mountainous Republic of the Northern Caucasus, the German Empire, the Central Caspian Dictatorship, and the British Empire, as part of the Middle Eastern theatre during World War I. The Caucasus campaign extended from the South Caucasus to the Armenian Highlands region, reaching as far as Trabzon, Bitlis, Mush and Van. The land warfare was accompanied by naval engagements in the Black Sea.