washington u.s. senators say sunday white house forthcoming detail military presence niger deaths four soldier early month want answer u.s. operations west african country republican senator lindsey graham democratic senate leader chuck schumer say separate interview support republican senator john mccain effort get answer pentagon ambush broadly u.s. fight isis niger graham schumer say unaware large u.s. presence country say congress need information could become long open-ended involvement know 1,000 troop niger graham say nbc meet press endless war without boundaries limitation time geography add get tell us mccain right say defense secretary jim mattis tell graham mccain serve chairman senate arm service committee friday military shift counter-terrorism strategy focus africa expand ability use force suspect terrorists attack early month u.s. officials suspect carry local islamic state affiliate throw spotlight u.s. counter-terrorism mission niger 800 u.s. troop u.s. president donald trump draw attention ambush spar last week democratic congresswoman frederica wilson criticize president say insensitive remark widow one fall soldier democrat schumer say program sunday like graham also unaware large presence u.s. troop niger also await answer military week say congress may need re-examine current authorization say could long open-ended involvement country region need look carefully brave new world set battle plan say add congress currently authorize action part authorization military use place 16 years since september 11 terror attack unite state would re-examine easy answer need look answer adequate say u.s. senators seek answer u.s. presence niger ambush