In which military conflict was the 'Osovets Offensive'?

The Osovets Offensive (Russian: Осовецкая наступательная операция) was part of the third and final phase of Operation Bagration, the Belorussian Strategic Offensive of the Red Army in summer 1944 between Russian forces and the forces of Nazi Germany.

The offensive began August 6 and was officially declared over as of August 14, although some of its objectives were not achieved until as late as January 1945.

Osovets is the Russianised version of the Polish name Osowiec / Ossowiec / Ossowitz.

The offensive commenced after the 2nd Belorussian Front had successfully taken Grodno and Białystok in the Belostock Offensive (Belostock is the Russianised version of the Polish name Białystok). The Front was issued with new objectives at the end of July, being ordered to move on Łomża (German: Lomscha) and Ostrołęka (German: Scharfenwiese) and to enlarge bridgeheads over the Narew river in preparation for a further advance into East Prussia.

Although there were many local actions (including attacks by Polish partisans, who had a strong presence in the area) the German defence line on the Narew held through the remainder of 1944, until the 2nd Belorussian Front's advance in the East Prussian Operation of January 1945.