He then called for volunteers, and the Public Safety Bureaus in the local districts turned over to them their police and militia, and established Feng as the General in command of a force, the Northeastern Loyal and Brave Army,[citation needed] of 15,000 men in the hills with the capital of Jilin City to his south and the metropolis of Harbin to his north.
There he was able to wreak havoc on the Japanese rail communications on the Chinese Eastern Railway running through his area of control.
In response the Japanese and Manchukoans launched two campaigns to clear Feng's Army out of the countryside.
Although surrounded, over half the guerrillas were able to slip through the encirclement and make good their escape to Rehe.
Subsequently he participated in Feng Yuxiang's Anti Japanese Allied Army, as its Fourth Route Army commander in chief, against Japan and their Manchukuoan allied forces in the Dolonor area of Chahar.