In 1944, after the Nazis suffered losses in the Eastern Front and the Red Army was approaching, the Lithuanian Territorial Defense Force (LTDF) was established under the command of general Povilas Plechavičius. The LTDF mission was to defend the country within its borders against the Red Army and the Soviet partisans. On 1 April 1944, the LTDF battalions entered Vilnius and confronted the Armia Krajowa (AK), which unsuccesfully attempted to capture the city before the Soviets (see Operation Ostra Brama). The AK tried to negotiate a non-aggression pact with Plechavičius, but the Lithuanian side demanded the Poles to abandon the Vilnius Region or subordinate themselves to Lithuanians. The 19 500 men LTDF disbanded itself after refusing to transcend the Lithuanian border and to aid the Nazis in the Eastern Front. Many of the former LTDF members later formed the core of the Lithuanian partisans (e.g. Jonas Žemaitis).