In the village of Serednie Wielkie, Lesko poviat, an 80–strong Border Patrol Guards WOP unit commanded by Captain Pilwiński fell into an UPA ambush.
The recklessness, even stupidity of commanders and soldiers is astonishing. „We were struck by a strange silence, no signs of life at all. People were nowhere to be seen, chickens, geese, and ducks were kept in pens far away from the houses, despite the frost, cattle and sheep were led out of the barns. It was as if the townspeople were expecting a fight soon. This calmness should have increased our vigilance, but it made it weaker. The soldiers started to leave their posts, leaving only a few colleagues in the hills, a few cattle were confiscated, and they were tied to carts”.
It was then that the UPA attacked. Poles report losses from 8 to 18 people: 16 soldiers, one officer and 1 policeman from Cisna, Jan Sikora — who covered the retreat of the army and his colleagues until the end. Ukrainian sources say that 30 Poles were killed. The Banderites released 25 captured soldiers with Lieutenant Gąsiak, when Lieutenant Colonel Kaminski threatened that he would otherwise remove Choceń and Serednie Wielkie from the face of the earth.

source: Żurek Stanisław, „Calendar of the genocide – January 1946”; in: „Borderlands Information Service” — web page: ksi.btx.pl [accessible: 2021.06.18]

source: Bata Artur, „Bieszczady. On the trail of battles with UPA bands.”; in: National Publishing Agency, in: 1984

Excerpt from the situational report of Stepan Golasz 'Mar', the OUN clerk from the 'Beskid' district about the murder of a Ukrainian in the Średnie Wielkie by Polish Army soldiers:
„April 29 [1946] the Polish Army in Średnie Wielkie caught the station guard, who was tied to a horse and led to Sanok where he was shot”.

source: „Wisti z terenu za czas wid 1.4 – 1.5.1946”; in: Poticzny P. J., Łyko I. (ed,), „Litopys UPA”, in: Toronto-Lviv 2002, vol. 34: „Lemkivshchyna and Peremyszczyna. Political reports (Documents)”, p. 77, in: orig. Ukrainian

source: Huk Bogdan with a group of friends, „Murders of the Ukrainian population 1944-1947”; in: portal: Ruthenian apocrypha — web page: www.apokryfruski.org [accessible: 2021.09.30]

Fragment of the field report of Stepan Golasz 'Mar', the SB‑OUN clerk of the 'Beskid' district, about the murder of a Ukrainian in Średnie Wielkie by Polish Army soldiers:
„On July 25, 1946, a detachment of the Polish Army from Baligród attacked the villages of Kalnica and Średnie Wielkie, looking for a detachment of 'Chrin'. In Kalnica, they burned down all the cellars and the newly built wooden huts. In Średnie, they burned down 4 houses, killed one boy, and beat other people with rifle butts, sticks and stones”.

source: „Wisti z terenu za czas wid 1.7 – 1.8.1946”; in: Institute of National Remembrance IPN Rzeszów, in: Acta OAIPN Rz 072/1, vol. 26, sh. 102

source: Huk Bogdan with a group of friends, „Murders of the Ukrainian population 1944-1947”; in: portal: Ruthenian apocrypha — web page: www.apokryfruski.org [accessible: 2021.09.30]