At the beginning of the war the units of the 17th Border Guards Detachment and various smaller elements (300 men altogether) were stationed at the Terespol Fortification.
At 4.15, supported by the heavy artillery barrage, the Wehrmacht assault group of the 3rd Battalion of the 135th Infantry Regiment entered the Terespol Fortification and rushed through the Terespol Gate into the Citadel. Some of the border guards were killed in the barracks within the island, many of them were wounded.
Three groups of the defenders were organized within the island. The commander of the transport company of the 17th Border Guards Detachment Senior Lieutenant A.S.Cherny headed the defence in the southern part of the Terespol Fortification near the garages. Senior Lieutenant F.M.Melnikov, in charge of the driving school, commanded the soldiers, trainees of the school, fighting in the north-western part of the island, not far from the building of the school. Along the bank of the Bug River the group under command of Lieutenant Zhdanov - about 80 people - took the defence.
It was on the first day of the war that the border guards of the Terespol Fortification surrounded and seized the German headquarters of the Wehrmacht 3rd Battalion, 135th Infantry Regiment and the 1st Battalion of the 99th Artillery Regiment. Thus, the commanders of the units were killed.
The border guards continued on fierce fighting. Due to the lack of ammunition in some places, they resorted to rifle-bayonet fighting. The enemy had to employ their reserves.
On June 24, the groups of A.S.Cherny and F.M.Melnikov were united. They decided to break through to the Citadel. Having failed to gain the foothold there, they began a spearhead towards the Kobrin Fortification. Only 13 of the 40 soldiers got to the casemates in the curtain wall between the North and the East Gates in the Kobrin Fortification. On June 28, Senior Lieutenant F.M.Melnikov was killed and shell-shocked Lieutenant A.S.Cherny was captured.
After June 24, at the Terespol Fortification the organized group under the command of Lieutenant Zhdanov continued the fighting. The trainee of the driving school of the Belarusian Border District M.I.Myasnikov recalled:
«...On the morning of June 25, the Germans began a heavy targeted fire attack on the island. They set fire to the garage, the storage room and the dining room. On June 27, a strong bombing of the island and the Citadel started again. Everything that had not been burned before was on fire. We lost more than half of our combatants on that day.
On the night of June 30, Lieutenant ordered to abandon the defended area, using the pre-dawn darkness, and swim to the Citadel.
The group started off. The Nazis noticed us again and opened fire. Only 18 of the 45 combatants reached the opposite river bank, three of them being seriously wounded.
By July 3, there were only 8 people alive...»