Sec. of State Rex Tillerson said Friday at a NATO summit in Brussels that U.S. sanctions enacted against Russia because of its invasion of Ukraine’s Crimean peninsula will remain in place.

“Crimea-related sanctions must remain in place until Russia returns control of the peninsula to Ukraine. Even in the face of Russia’s aggression, Ukraine has accomplished a great deal domestically,” Tillerson said during a meeting of the NATO-Ukraine Commission, according to CBS News.

“We applaud recent reform successes, including anti-corruption efforts and pursuing necessary reforms to meet IMF conditionality.”

The Obama administration implemented various sanctions against the Russian government in 2014 over the invasion of Crimea.

Tillerson, who did business in Russia as CEO of ExxonMobil, said that that invasion “shook the very foundations of security and stability in Europe.”

“We do not, and will not, accept Russian efforts to change the borders of territory of Ukraine,” he continued, adding that “the United States sanctions will remain until Moscow reverses the actions that triggered our sanctions.”

Tillerson’s comments undercut predictions made by Democrats that the Trump administration planned to relax sanctions against Russia.

Democratic California Rep. Maxine Waters made such a prediction earlier this week.

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