US State Department's spokesperson Heather Nauert said during briefing that Washington was against a possible purchase of Russian S-400 air defense systems by its allies around the world.

Previously, Russia and Turkey signed a loan agreement on the sale of the S-400s to Ankara, causing a backlash from the US that threatened to impose sanctions against if Turkey proceeded with the agreement.

Turkish Defense Minister Nurettin Canikli then responded to Washington's threats by warning US against preventing the new F-35 jets from being shipped in accordance with their contract unless it abandons its agreement with Russia on the S-400 delivery, calling Washington's threats a "blackmail."