The bridgeheads at Serock had been established by the Soviet 65th Army at the end of the Lublin -- Brest Offensive .
The bridgeheads at Serock are the confluence of the Bug and Narew Rivers .
The bridgeheads at Serock , the confluence of the Bug and Narew Rivers , had been established by the Soviet 65th Army at the end of the Lublin -- Brest Offensive .