An agreement for Turkey to purchase S-400 surface-to-air missile systems from Russia may be signed this week, Turkish Foreign Minister Mevlut Cavusoglu said on Thursday, according to Reuters. Speaking at a joint news conference with his Maltese counterpart Carmelo Abela, Cavusoglu said technical work would begin with Russia on setting up the S-400 systems. Last week, President Recep Tayyip Erdogan also said the deal with Russia would be finalized this week.