Shugaban Amurka Donald Trump ya yabawa yarima mai jiran gado a Saudi Arabia, Mohammed bin Salman yayin wata ganawa da suka yi a gefen taron kolin manyan kasashe ashirin mafi karfin tattalin arziki a duniya, G20 a kasar Japan, yana mai kiransa "abokina, wanda ya yi aikin azo a gani".