Wednesday : Armed , disabled man wheeled himself out of a Virginia facility , taken into custody . Standoff : Wednesday afternoon ; number of hostages was uncertain . He entered Wytheville , Virginia , post office and fired a shot , mayor surrendered .
NEW : Armed , disabled man wheeled himself out of a Virginia facility , taken into custody . Standoff began Wednesday afternoon ; number of hostages was uncertain . Man entered Wytheville , Virginia , post office and fired a shot , mayor says .