Tactical Hellenic Army victory Provisional Democratic Government Kingdom of Greece War Operation Koronis (Greek: Επιχείρηση «Κορωνίς», "crown" in Greek) was a military campaign launched by the royalist government in Athens against the main stronghold of the communist forces during the Greek Civil War.

The communist defenses were two lines of fortifications with minefields and concealed bunkers.

After neutralizing the minefields by forcing herds of animals to walk over them, the government army launched simultaneous attacks from two sides.

With heavier casualties against a numerically superior opponent, the communists had their wounded and artillery moved across the border to the People's Republic of Albania.

Although the Hellenic Army failed to completely defeat the communists, the latter realized the lack of assistance they received from the Soviet Union, and the royalist government became stronger with assistance from the United States (Truman Doctrine).