The Osovets Offensive was part of the third and final phase of Operation Bagration, the Belorussian Strategic Offensive of the Red Army in summer 1944. 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 nameOsowiec / Ossowiec / Ossowitz.
Operational goals
The offensive commenced after the 2nd Belorussian Front had successfully taken Grodno and Białystok in the Belostock Offensive. The Front was issued with new objectives at the end of July, being ordered to move onŁomża and Ostrołęka and to enlarge bridgeheads over the Narew river in preparation for a further advance into East Prussia. The defenders were somewhat aided by fortifications from previous eras, including a major Imperial Russian-era fortress complex at Osowiec on the Biebrza River that was a scene of a siege in 1915 during the First World War, and which was partly demolished by Wehrmacht troops in 1939 before its hand-over to the Red Army. There were also substantial Soviet border fortifications remaining from the Molotov Line located 20 km west of the old fortress.
The offensive began on August 6 with further penetrations by the 2nd Belorussian Front west of Bialystok. The approaches to Osowiec were heavily defended; the 1st Guards Assault Engineer Brigade was required to establish river crossings under fire. Units of the Front stormed and took the fortress, after a heavy air bombardment by Major-General Georgy Baydukov's 4th Assault Aviation Corps, on August 14. Joseph Stalin's Order no. 166 for that day noted the capture of the fortress and congratulated the units and commanders involved. August 14 is noted as the end of the offensive in official Soviet historiography, but in fact attempts continued to seize bridgeheads over the Narew throughout the remainder of August. The 49th Army, however, found that the German defences on the approaches to Lomza were difficult to overcome, sustaining many casualties. Lomza itself was not taken until mid-September; there were intense battles along the Narew as Second Army was progressively reinforced and attempted to crush the bridgeheads.
Aftermath
Although there were many local actions 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.
