The Holy Bible, Ezekiel 38

The battle of Gog, from the land of Magog, against Israel will usher in the Second Coming—The Lord will come amid war and pestilence, and all men will shake at His presence.

The Holy Bible, Ezekiel 39

Gog and the land of Magog will be destroyed—For seven years the people in the cities of Israel will burn the weapons of war—For seven months they will bury the dead—Then will come the supper of the great God and the continued gathering of Israel.

The Guide to the Scriptures: Gog

A king of Magog. Ezekiel prophesied that Gog would invade Israel at the time of the Lord’s Second Coming (Ezek. 38–39). Another battle, called the battle of Gog and Magog, will occur at the end of the Millennium (Rev. 20:7–9; D&C 88:111–116).

Old Testament Student Manual Kings–Malachi, The Battle of Armageddon: A Prophetic View

At the very moment of the Second Coming of our Lord, ‘all nations’ shall be gathered ‘against Jerusalem to battle’ (Zech. 11; 12; 13; 14), and the battle of Armageddon (obviously covering the entire area from Jerusalem to Megiddo, and perhaps more) will be in progress. As John expressed it, ‘the kings of the earth and of the whole world’ will be gathered ‘to the battle of that great day of God Almighty, … into a place called in the Hebrew tongue Armageddon.’ Then Christ will ‘come as a thief,’ meaning unexpectedly, and the dramatic upheavals promised to accompany his return will take place. (Rev. 16:14–21.) It is incident to this battle of Armageddon that the Supper of the Great God shall take place (Rev. 19:11–18), and it is the same battle described by Ezekiel as the war with Gog and Magog.

Ezekiel and Jeremiah indicated areas that will be involved and named Israel as the target of the war:
Ezekiel named Gog of the land of Magog, the prince of Meshech and Tubal, as the leader of the forces that would come against Israel (see Ezekiel 38:1–3). Magog, Meshech, and Tubal were ancient peoples in the northern part of Asia Minor (see Notes and Commentary on Ezekiel 38:2–6). Gog is a symbolic name for the leader or leaders of this great evil power that will arise in the last days.
Ezekiel named Persia, Ethiopia, Libya, Gomer, and Togarmah as being in alliance with Gog (see Ezekiel 38:2–6; see also Notes and Commentary on Ezekiel 38:2–6 and the Bible Dictionary).

These designations refer to general areas of the ancient world, so a list of modern nations fighting in Armageddon cannot be compiled from these sources. Elder Bruce R. McConkie said: “The prophecies do not name the modern nations which will be fighting for and against Israel, but the designation Gog and Magog is given to the combination of nations which are seeking to overthrow and destroy the remnant of the Lord’s chosen seed.” (Mormon Doctrine, p. 298.)