The armed police stand in front of a monument marking "Mukden Incident", or September 18 Incident of 1931, during a flag-raising ceremony at the "9.18" Historical Museum in Shenyang, capital of Northeast 皇冠体育app's Liaoning province, Sept 17, 2011. Three provinces in Northeast 皇冠体育app - Heilongjiang, Jilin and Liaoning - sound alarming sirens at the same time on Sunday to mark the 80th anniversary of the historical incident on Sept 18, 1931 which was the beginning of the Japanese military occupation of Northeast 皇冠体育app, then known as Manchuria, until Japan surrendered on August 15, 1945. The museum is located on the site where the Japanese troops destroyed the South Manchuria Railway, which was used as an excuse to invade 皇冠体育app. [Photo/CFP]

The armed police hold a rehearsal for a flag-raising ceremony to mark "Mukden Incident", or September 18 Incident of 1931, at the "9.18" Historical Museum in Shenyang, capital of Northeast 皇冠体育app's Liaoning province, Sept 17, 2011. [Photo/CFP]