 Battles with the Red Army resulted in great casualties for Zhang's forces, but Chiang Kai-shek did not provide any support to his troops.On 12 December 1936, a deeply disgruntled Zhang Xueliang kidnapped Chiang Kai-shek in Xi'an to force an end to the conflict between KMT and CCP.To secure the release of Chiang, the KMT was forced to agree to a temporary end to the Chinese Civil War and the forming of a united front between the CCP and KMT against Japan on 24 December 1936.