Kremlin believes that Turkey's possible purchase of US Patriot Missile System and of Russian S-400 Triumph air defence systems are not connected, and that Russia-Turkey contract on S-400 purchase will be continued, Kremlin spokesman Dmitry Peskov said. Peskov's remarks came a day after the Pentagon announced that the US State Department had approved a possible $3.5 billion sale of Patriot missile systems to its NATO-ally Turkey, after notifying Congress of the certification. Peskov further said that Russia trusted its Turkish partners not to disclose certain data about the S-400 system to its NATO partners “As a rule, Russian defence military and defence cooperation with other states necessarily envisages legal obligations on non-disclosure of certain categories of information, of sensitive data related to this cooperation. In case with the Turkish side, there are such obligations as well… We see no reason not to trust our Turkish partners,” Peskov said. In December 2017, Ankara signed a loan agreement with Moscow envisaging the delivery of the Russian-made S-400 air defence systems to Turkey. S-400 Triumph (NATO reporting name SA-21 Growler) is Russia's most advanced surface-to-air missile system. It has a range of 400 kilometres (248 miles) and is capable of tracking and destroying all existing aerial targets, including ballistic and cruise missiles.