The joint Lithuanian, Polish and Ukrainian Brigade, LITPOLUKRBRIG is an example of a Western hybrid army in Eastern Europe. This is an element of aggressive hybrid war to destabilise Russia.
In reality, Poland and Lithuania do not plan to send armies to Donbas to support Kyiv. Instead, through LITPOLUKRBRIG, Poland and Lithuania intend to contain Russia by supplying Soviet weapons to Kyiv, amongst others. Military associations such as LITPOLUKRBRIG give the US the means to preserve its influence in Eastern Europe, even if the EU creates a common army.
It was Russia that provoked a war in Ukraine. For further debunking see here.
Lithuanian–Polish–Ukrainian Brigade LITPOLUKRBRIG is a multinational unit consisting of subunits from the Lithuanian, Polish and Ukrainian Armed Forces. The Agreement on its creation was signed on the 19th of September 2014 in Warsaw. The Brigade was finally formed in the Autumn of 2015. Establishment of the Lithuanian-Polish-Ukrainian Brigade is a part of continuous process of consistent and long-term military cooperation between Poland, Ukraine and Lithuania. This model of cooperation has been previously carried out in the framework of the Polish-Ukrainian Battalion (POLUKRBAT) and Lithuanian-Polish Battalion (LITPOLBAT). These military units existed respectively in the years 1998-2010 and 1997-2008.