moscow russia offer turkey partial finance ankara purchase s-400 surface-to-air missile systems interfax news agency report tuesday cite russian presidential aide turkey talk buy system year washington nato ally see move snub weapons integrate alliance defenses turkish russian officials would meet finalize deal next week turkish president tayyip erdogan say monday russian president vladimir putin say ankara credit defense industry would sign turkey near future ask interfax whether russian finance would cover full cost deal russian presidential aide vladimir kozhin say whole partially technical question discuss interest rate everything finance ministry say deal turkey expect receive first missile system 2019 turkish defence minister nurettin canikli say november deal include two s-400 systems third optional one russian credit cover part s-400 missile deal turkey agency