[6] On 26 April 1918, his signature appeared on a telegram sent the following day on behalf of the government and the Rada of the Belarusian Democratic Republic to German Emperor Wilhelm II.

The telegram expressed gratitude for the liberation of Belarus and requested support for the Belarusian Democratic Republic and its alliance with Germany.

[10] He was a member of the Belarusian Democratic Republic delegation that traveled to Kyiv on 19 September 1918 for talks with the government of the Ukrainian State.

On 19 September 1919, as a member of the Convention of Seniors of the Rada of the Belarusian Democratic Republic, he participated in a meeting with the Polish Chief of State Józef Piłsudski at the Nobility House in Minsk.

During the meeting, the delegation asked Piłsudski to recognize the independence and integrity of the Belarusian Democratic Republic, allow the restoration of its organs, gradually transfer power to the Rada, provide a loan, form Belarusian military units alongside the Polish army, and jointly fight the Bolsheviks.

[12] At that time, Antoni Owsianik was a proponent of an agreement with Poland, the creation of a Belarusian army under Polish command, and discussions about forming a Belarusian-Polish federation, which he viewed purely pragmatically.

[13]In mid-October 1919, he became part of the delegation of the Belarusian Central Council of Vilna and Grodno Regions, which went to Warsaw for talks with Polish authorities on Belarusian-Polish cooperation.

[14] On October 22, Antoni Owsianik was formally approved by Józef Piłsudski as a member of the Belarusian Military Commission.

In the fall of 1919, an agreement was signed in Smolensk between the Bolsheviks and the Byelorussian Soviet Socialist Republic, under which the latter agreed to extend their influence on the Belarusian Military Commission.

[16] However, the accusations made by the report directly against Antoni Owsianik only state that the Byelorussian Soviet Socialist Republic decided to contact him.

[19] On October 3, the Supreme Command of the Polish Army [pl] announced the acceptance of his resignation along with the entire current commission.

[21] After reaching an agreement on this matter, he oversaw the development of Belarusian units in Lithuania, which Lastouski's government intended to use against Poland in the event of a Lithuanian-Polish conflict.