Former Commander-in-Chief of the Petrograd military okrug , Colonel Georgi Polkovnikov , pronounced Statement himself as commander of the so-called `` Salvation Army '' ( войска спасения ) and ordered Arranging his garrison not to execute orders issued by the Petrograd Military Revolutionary Committee ( PMRC ) , arrest Arrest its commissars , and send Sending representatives from all military units to Nikolayevskoye School of Engineers ( a.k.a .