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.
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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."