washington u.s. president donald trump give defense secretary jim mattis authority set troop level afghanistan u.s. official tell reuters tuesday open door future troop increase request u.s. commander official speak condition anonymity say immediate decision make troop level set 8,400. pentagon decline comment decision similar one announce april apply u.s. troop level iraq syria come mattis warn congress u.s.-backed afghan force beat taliban despite 15 years war `` win afghanistan right `` mattis say testimony senate arm service committee early tuesday `` correct soon possible `` commentary troop surge afghanistan terrible idea mattis say taliban surge moment something say intend address former u.s. official say decision might allow white house argue micromanaging much administration former president barack obama sometimes accuse critics say delegate much authority military shield trump political responsibility battlefield setbacks could reduce chance diplomats warn potential blowback military decisions four months since army general john nicholson lead u.s. international force afghanistan say need thousand additional force potentially draw u.s. ally current former u.s. officials say discussions revolve around add 3,000 5,000 troop force expect largely comprise trainers support afghan force well air crew deliberations include give authority force grind take aggressive action taliban fighters u.s. officials question benefit send troop afghanistan politically palatable number would enough turn tide much less create stability security date 2,300 americans kill 17,000 wound since war begin 2001. increase several thousand troop would leave american force afghanistan well 2011 peak 100,000 troop afghan government assess u.s. military control influence 59.7 percent afghanistan 407 district feb. 20 nearly 11 percentage-point decrease time 2016 accord data release u.s. special inspector general afghanistan reconstruction truck bomb explosion kabul last month kill 150 people make deadly attack afghan capital since taliban oust 2001 nato-led coalition rule country five years saturday three u.s. soldier kill afghan soldier open fire eastern afghanistan broad regional u.s. strategy afghanistan remain unclear mattis promise tuesday brief lawmakers new war strategy mid-july widely expect call thousands u.s. troop senator john mccain chairman arm force committee press mattis deteriorate situation tuesday hear say unite state urgent need change strategy increase resources turn situation around recognize need urgency mattis say trump give u.s. military authority set afghan troop level u.s. official