The US Department of State has expressed concern over Turkey’s purchase of the Russian-made S-400 missile defense system.

Commenting on the information that Russia had announced that it will move up the scheduled delivery of this air defense system to Turkey from 2020, which it was originally scheduled, to 2019, State Department Spokesperson Heather Nauert noted that the US had repeatedly said that it was against any NATO ally, especially Turkey, acquiring this system.

“It goes against our policy to have a NATO ally such as Turkey use an S-400 system,” she said at Thursday’s press briefing. “Part of the problem with that, it is – that it is not interoperable with other NATO systems. And so we are against the – having some of our partners and allies around the world potentially purchase S-400s.”

And when asked whether this would trigger US sanctions on Turkey, Nauert responded: “We have made very clear what could trigger sanctions for other countries and entities around the world.”