abu dhabi u.s. president donald trump defense secretary say bad weather force scrap visit afghanistan sunday add review next step war discussions afghan president ashraf ghani top u.s. commander put thoughts together defense secretary jim mattis tell reporters abu dhabi debut trip middle east u.s. general john nicholson commander u.s. international troop afghanistan say month nato-led force afghanistan enough troop carry counterterrorism missions shortfall thousand major role advise afghan security force mattis say speak several hours sunday via video-link nicholson disclose whether favor send u.s. force mattis also say speak ghani length leave munich germany saturday far trump offer little clarity whether approve force afghanistan 8,400 u.s. troop remain 15 years islamist taliban government topple wait assessment assessment intelligence community open advice mattis say first get formulate stand afghan government force control two-thirds national territory struggle contain taliban insurgency since bulk nato soldier withdraw end 2014. government also struggle militants particularly islamic state afghanistan branch islamic state claim responsibility suicide attack kill least 22 people feb. outside afghanistan supreme court number provincial capitals pressure taliban afghan government force suffer high casualty rat 5,500 kill first eight months 2016 afghan security force pay heavy price keep taliban back foot pay hold mattis say taliban bad position today even though equate success side u.s. defense secretary scrap afghan trip due weather