In January 1918, two months after the Bolshevik seizure of power in Russia, the Sovnarkom, the highest government authority under the Bolshevik system, issued a decree which called for the withdrawal of Russian troops from the Caucasus Front. This move threw the Armenian leadership in the Transcaucasia into a panic, since it removed from the region the only force capable of protecting the Armenian people from the Ottoman Empire, which had effectively exterminated its Armenian population through systematic massacres and deportations.
Armenians attempted to stall the Ottoman advance as they created a small Armenian army to take up the positions the Russians had abandoned.
General Tovmas Nazarbekian was selected as its commanding officer and Drastamat Kanayan was appointed as civilian commissar. But in May 1918, just two months after the Brest-Litovsk Peace Treaty was concluded with the Russian SFSR, elements of the Ottoman Third Army crossed into Eastern Armenia and attacked Alexandropol (modern-day Gyumri). The Ottoman Army intended to crush Armenia and seize Russian Transcaucasia and the oil wells of Baku. The German government, the Ottoman Empire's ally, objected to this attack and refused to help the Ottoman Army in the operation.
At this time, only a small area of historical Armenian territory which used to be a part of the Russian Empire remained unconquered by the Ottoman Empire, and into that area hundreds of thousands of Armenian refugees had fled after the Armenian Genocide. The Ottoman Forces began a three-pronged attack in an attempt to finally overwhelm and conquer the rest of Armenia. When Alexandropol fell, the Ottoman Army moved into the territory of Ararat Valley – the heart of Armenia.
The Ottoman offensive was viewed by Armenians with foreboding. With nowhere else left to retreat, they decided to make their stand and prepare for the upcoming battle.
Acting under Minister of War Enver Pasha's request, Miralay (Colonel) Kâzım Karabekir Bey's I Caucasian Corps and Mirliva Yakub Shevki Pasha's II Caucasian Corps put into action in the direction of Karakilisa (modern-day Vanadzor), Sardarabad, Tiflis (modern-day Tbilisi) and Yerevan on 20 May.
The Ottoman force reached Karakilisa on May 20 without resistance. Only a single combat action took place near the village of Karzakh. The detachment commanded by Zihni Bey, that advanced forward in Sardarapatarea, reached the station of Alagöz (modern-day Aragats) and line of Mahtaka. On May 21, the detachment of Zihni Bey defeated an Armenian unit composed of 600 infantry and 250 cavalry, and then took Sardarabad. From there, their forces started advancing toward Yeghegnut.
Armenian general Movses Silikyan ordered elements of the 5th Armenian Regiment under Poghos Bek-Pirumyan, a reserve guerrilla unit, and a special cavalry regiment to check the advance of the Ottoman army. An offensive was launched on May 22 and the Armenian forces were successful in halting the Ottomans in their tracks and forcing Yakub Shevki Pasha's forces into a general rout (retreating nearly 15-20 kilometers in a westerly direction). The Ottoman command, however, was able to recuperate from its losses and reorganized its forces near the mountain heights on the north-west bank of the Araks river. Repeated attempts to cross the river were met with fierce resistance by the 5th Armenian Regiment.
On May 24, several more skirmishes took place between the Armenian and Ottoman forces. However, attempts to dislodge the Ottomans from their well-entrenched positions the following day by Poghos Bek-Pirumyan's and other commanders' forces were met with failure. On May 27, an Armenian force commanded by Colonel Karapet Hasan-Pashayan performed a flanking maneuver and struck the Ottoman positions from the rear while the rest of the Armenian forces pounded the main Ottoman positions. An Ottoman force based in Talin was sent to alleviate it by attacking the Armenian rear, but was unable to change the outcome of the battle. Suffering heavy losses, Ottoman commanders ordered a general retreat as the surviving elements of the Ottoman army were put to flight.
With the Ottoman forces in a full rout, General Silikyan wished to press on his advantage with the hope of dislodging the Ottomans from Alexandropol and Kars. But, almost immediately, he was informed of the ongoing negotiations between the Ottoman leadership and the Armenian National Council in Tiflis and was told by Corps Commander Tovmas Nazarbekian to cease military operations in the region. Though members of the National Council were widely criticized for issuing this order at the time, this decision was carried out on account of the fact that the ammunition stores had been all but been depleted and Ottoman commanders had received fresh reinforcements.
The Ottoman defeats at Sardarabad, Bash Abaran, and Karakilisa staved off the annihilation of the Armenian nation, and the victories here were instrumental in allowing the Armenian National Council to declare the independence of the First Republic of Armenia on May 30 (retroactive to May 28). Though the terms that Armenia agreed to in the Treaty of Batum (June 4, 1918) were excessively harsh, the little republic was able to hold out until the Ottomans were forced to withdraw from the region with the end of World War I in late 1918.