Solor Query Not giving data when using FileldFilters

$searchQuery.Add("FieldFacets", "category,count,12,0,0!0||user,count,12,0,1||group,count,12,0,1||tag,count,12,0,1")
$searchQuery.Add("FieldFilters", "0,category,forum||1,group,113||2,tag,ABC OR 2,tag,DEF|| 4,threadstatus,Answered")
$searchQuery.Add("Collapse", true)
$searchQuery.Add("PageSize", $pageSize)
$searchQuery.Add("PageIndex", $ajaxCurrentIndex)

#set ($results = $core_v2_searchResult.List($searchQuery))

Above Query is giving data for the Forum that contain tag as ABC but not giving result for the Forum that contain tag  DEF  Why?

can any body let me know how we can apply OR operator into multiple tag.