MOSCOW (Reuters) - Russia will offer Turkey partial financing for Ankara s purchase of S-400 surface-to-air missile systems, the Interfax news agency reported on Tuesday, citing a Russian presidential aide. Turkey has been in talks to buy the system for more than a year. Washington and some of its NATO allies see the move as a snub because the weapons cannot be integrated into the alliance s defenses. Turkish and Russian officials would meet to finalize the deal next week, Turkish President Tayyip Erdogan said on Monday.  Russian President Vladimir Putin said in Ankara that credit for the defense industry would be signed with Turkey in the near future. When asked by Interfax whether the Russian financing would cover the full cost of the deal, Russian presidential aide Vladimir Kozhin said:  Not the whole, partially.   Technical questions are being discussed, the interest rate. Everything is in the Finance Ministry,  he said of the deal. Turkey expects to receive the first missile system in 2019, Turkish Defence Minister Nurettin Canikli said in November. The deal included two S-400 systems and a third optional one. 