Edited sentence: A number of Special Operations Executive (SOE) agents were sent to Yugoslavia to determine the facts on the ground.At the Teheran Conference of 1943 and the Yalta Conference of 1945, Soviet premier Joseph Stalin and British Prime Minister Winston Churchill decided to split their influence in Yugoslavia in half.However, Tito's Partisans managed to break through the encirclement, cross the river, and engage the Chetniks.In the meantime, the Allies stopped planning an invasion of the Balkans and finally rescinded their support for the Chetniks and instead supplied the Partisans.In the meantime, the Germans, also aware of the growing importance of Yugoslavia, decided to wipe out the Partisans with determined offensives.Later during the War, the Allies were seriously considering an invasion of the Balkans, so the Yugoslav resistance movements increased in strategic importance, and there was a need to determine which of the two factions was fighting the Germans.The Chetniks participated with a significant, 20,000-strong, force providing assistance to the German and Italian encirclement from the east (the far bank of the river Neretva).The Chetniks, by this time, had agreed to provide support for the German operations, and were in turn granted supplies and munitions to increase their effectiveness.The Partisans continued on, and later again escaped the Germans in the Battle of Sutjeska.The conflict resulted in a near-total Partisan victory, after which the Chetniks were almost entirely incapacitated in the area west of the Drina river.The first of these large anti-Partisan offensives was Fall Weiss, also known as the Battle of Neretva