Wikipedia
The Dekemvriana (, "December events") refers to a series of clashes fought during World War II in Athens from 3 December 1944 to 11 January 1945 between the Greek left-wing Resistance forces (the EAM- ELAS, the KKE) and the British Army supported by the Greek Government, the Cities Police and the far-right Organization X of Georgios Grivas.
The conflict was the culmination of months of tension between the communist EAM-ELAS, the country's largest resistance movement, which controlled most of Greece, and the British-backed government, which had returned from exile upon the Germans' withdrawal in October 1944. Although EAM had initially participated in the government, mounting differences with the traditional bourgeois parties led to the resignation of its ministers. On 3 December, a huge pro-EAM rally in central Athens was shot upon by the Police on orders from Angelos Evert, leaving 28 protesters dead and 148 wounded. The killings ushered a full-blown armed confrontation between EAM and the British, under General Ronald Scobie.
The clashes were limited to Athens, and elsewhere in Greece, the situation remained tense but peaceful. The Dekemvriana ended with the defeat of EAM-ELAS, leading to its disarmament in the Varkiza Agreement. This first defeat broke the power of EAM and was followed by a period of " White Terror", which contributed to the outbreak of the Greek Civil War in 1946.