In late April and early May 1944, the German authorities decided to transfer a significant part of the police duties in Lithuania to the newly created LTDF formation, which was ordered to initiate a wide anti-partisan operation against the Polish and Soviet partisans in the area. Three Lithuanian battalions were dispatched to man garrisons in and around the town of Oszmiany. The AK commander for the Vilnius region Aleksander "Wilk" Krzyżanowski mobilized the region's partisan troops in response, but they were ordered not to engage the German allied LTDF in order to prevent the escalation of Polish-Lithuanian hostilities. The Lithuanian troops, however, satisfied by their perceived superiority, started suppressing the local Polish communities suspected of harboring the anti-Nazi partisans; numerous war crimes were committed by the LTDF, notably atrocities against Polish civilians in Pawłów, Graużyszki and Sieńkowszczyzna. Faced with the need to protect Polish civilians, the AK decided to fight back in early May, and organized a concentrated assault against the fortified Lithuanian positions around the village of Murowana Oszmianka. On May 10, AK units were ordered to prepare an assault against one of the larger LTDF units in the region.
Plan
Major Czesław Dębicki "Jarema" was chosen to be the commander of the five AK brigades that were to attack the LTDF positions in Murowana Oszmianka. The AK reconnaissance perceived that their enemy's strength was four companies in Murowana Oszmianka, two companies in Tołominowo, and a strong German garrison in Oszmiany. The strength and quality of the enemy's forces were ascertained to be superior by about 150 men, and created the need for a surprise attack, which was vital for the Polish plan and ultimate Polish victory. On May 12 a detailed plan was created. It called for:
4 platoons of the 8th brigade to attack Murowana Oszmianka from the south-east, converging on the church;
The 3rd brigade would attack Murowana Oszmianka from the north-west;
The 13th brigade would secure the Murowana Oszmianka-Tołominowo road, possibly attack Tołominowo, and prevent cooperation between the enemy's forces;
The 9th brigade would secure the Murowana Oszmianka-Oszmiany road;
The Oszmiana-Murowana Oszmianka bridge would be blown up to prevent German armor from engaging in what became a significant Polish victory;
Communication lines between Wilno-Oszmiana would be cut off;
The 12th brigade and remaining cavalry platoon of the 8th brigade would be held in reserve;
Positions would be taken at dusk; all units would disengage by dawn to avoid a counterattack by the German Luftwaffe;
The assault would begin at 2300 hours.
The battle
On the night of May 13, the 3rd Brigade of the AK assaulted the village from the west and north-west, while the 8th and 12th Brigades attacked from the south and east. The remainder of the Polish forces secured the Murowana Oszmianka-Tołminowo road. The defences, reinforced with concrete bunkers and trenches, were manned by elements of the 301st of the LTDF. This detachment was already wavering following a defeat at Graużyszki on May 5, where they were dispersed by the 8th and 12th Brigades of the Home Army and suffered 47 casualties. The assault was a success, partially because other Lithuanian garrisons in nearby towns did not move from their posts; German reinforcements were stopped by sabotage of bridges and delaying actions. The 3rd company of the 301st battalion was also engaged in the vicinity of the nearby Tołominowo village by the 13th Brigade. This engagement also ended with a decisive Polish victory.
Aftermath
During the battles in Murowana Oszmianka and Tołminowo, the 301st battalion was practically wiped out; only the 4th company managed to evade Polish forces and retreat. The LTDF lost at least 50 men, with 60 more wounded and more than 300 taken prisoner of war. After the battle, all Lithuanian prisoners of war were disarmed and released with only their long johns and helmets on. The Lithuanian officers were given letters from the Vilnius region AK commander, Aleksander "Wilk" Krzyżanowski, addressed to the LTDF commander, general Povilas Plechavičius, appealing for a stop to Lithuanian-Nazi German collaboration, an end to Lithuanian anti-Polish policies and a joint effort to combat the Germans; Lithuanians refused and demanded that the Poles either abandon the Vilnius Region or subordinate themselves to the Lithuanians in their struggle against the Soviets. After their defeat in the battle of Murowana Oszmianka and other skirmishes against the Home Army, the LTDF became so weakened that Povilas Plechavičius and his officers were judged to be useless by the Germans and were relieved of command. Soon afterwards, they were arrested and their unit dissolved.
