washington leaders u.s. senate intelligence committee say wednesday issue whether president donald trump 2016 election campaign collude russia remain open question panel intensify probe matter republican chairman richard burr democratic vice chairman mark warner also warn risk future u.s. elections pose russia include expect closely contest election next month governor warner home state virginia burr tell reporters committee plan conduct 25 interview witness month describe goal finish year main congressional investigation russian meddle aspirational point issue collusion still open burr say stand alongside warner press conference provide update investigation come determination collusion say burr say want much conclude investigation height campaign november 2018 u.s. mid-term elections 435 seat house representatives one third 100-seat senate grab warner say unite state need whole-of-government approach combat interference u.s. elections russian active measure efforts end election day 2016 say trump call allegations campaign collusion moscow hoax face question matter since take office january special counsel appoint justice department robert mueller conduct separate probe could lead criminal charge russia deny meddle u.s. intelligence agencies conclude russia interfere election try help trump defeat democratic candidate hillary clinton campaign hack release embarrass email disseminate propaganda via social media discredit campaign burr say committee agree intelligence community conclusion russia interfere committee continue look evidence see hint collusion burr say even go discuss initial find get tremendous amount document still go through say panel conduct 100 interview last 250 hours nine-month-old probe currently book balance month 25 additional interview already come committee members investigators include president son-in-law adviser jar kushner former trump campaign manager paul manafort social media executives officials twitter inc twtr.n wednesday representative kushner ivanka trump deny report usa today couple re-routed personal email family business among witness appear future public committee hear trump personal attorney michael cohen executives facebook inc fb.o twitter alphabet inc googl.o google warner burr urge american election officials political campaign take threat russian interference seriously walk away believe russia currently active try create chaos election process assume tactics saw montenegro france belgium unite state continue test within structure election process burr say burr say committee hit wall investigation former british spy explosive dossier purport russian support trump 2016 campaign former mi6 officer christopher steele compile dossier trump tell former fbi director jam comey contain salacious material businessman-turned-president trump associate call dossier content false several occasion make attempt contact mr. steele meet mr. steele burr say offer go unaccepted committee really decide credibility dossier without understand things like pay source sub-sources burr add correct version story remove quote incorrect attribution sixth paragraph replace another quote russia-trump campaign collusion 'open issue u.s. senate panel chiefs