[13] In one incident in August 20, 1948, the armed group of Markos Vafeiadis was ambushed by the Greek government forces near the Albanian border.

Giorgis Blanas, also known by his nom-de-guerre Kissavos, who was fighting on the side of the Democratic Army, wrote the following about this phase of the operation:[15] Both Great Britain and the United States objected an assault against Albania.

The attack was carried out by six army divisions that had a separate strength of 17 brigades, 9 battalions of light infantry, and were supported by 110 artillery guns, a number of tanks and armored vehicles, as well as 87 airplanes.

Henceforth, the forces of the Democratic Army in Vitsi were in a desperate situation, and on the night of August 14–15, 1949, they retreated and took refuge in Albanian territory.

[18] The third and final phase aimed at the capture of the area of Grammos with a decisive attack, in order to neutralize the remaining forces of the Democratic Army and block their escape to Albania.

After the fall of Vitsi, Grammos was the last stronghold of the Democratic Army left in Greece, where all their remaining forces had gathered.

Pyrsos III would be directed by Lieutenant General Thrasyvoulos Tsakalotos, with five army divisions at his disposal, an independent brigade, four light infantry regiments, 120 artillery guns, plenty of armored vehicles suitable for rough terrain, and the entire air force which was reinforced with Helldiver dive bombers equipped with Napalm bombs;[19] this was the first time such bombs were used by Greek Air Force.

However, the forces of the Democratic Army were poorly armed and supplied, and also tired from their continuous presence on the front line due to lack of reserves.

Nikos Zachariadis on the other hand, tried to remain optimistic, and issued the following:[20] In the early hours of August 25, 1949, the forces of the National Army were ordered by General Tsakalotos to move against their targets and execute the plan of Pyrsos III.

King Paul and the American Lieutenant General James Van Fleet, were invited by Tsakalotos in a special vantage point in the Ammouda region of Grammos, from where they watched the successive waves of the National Army's attack with military binoculars.

The 9th division, advanced to the rear of the rebels, and occupied the Porta Osman crossing; the main gateway of communication between the Greek and Albania territories in the area of Grammos.

According to the data of the National Army's general staff, in September 1949 there were still 2,150 rebels throughout Greece, who were gradually decreasing due to many desertions.

[21] The Albanian government fearing an attack by the Greek army, disarmed the communist guerrillas that were located in Albania and insisted that the later should leave the country.

Soviet policy also dictated that any further Albanian involvement in the Greek civil war should be avoided, otherwise the independence of Albania would have been found in jeopardy.

[22] In September, the Greek minister of military affairs warned that if the Albanian state authorities continued to support the retreating insurgents within their territory, Greece would invade by invoking the right of ‘self-defence’.