US President Donald Trump has reportedly told Moscow he expects Russia to return the Crimean peninsula to Ukraine, White House Press Secretary Sean Spicer told reporters Tuesday.

Addressing the resignation of Trump's national security adviser Michael Flynn following reports that he discussed American sanctions against Russia with the country's ambassador before Trump was sworn in, Spicer said that Russia had “seized" Crimea from Ukraine under the Administration of former President Barack Obama, and that the Trump Administration's Ambassador to the UN, Nikki Haley, has already "strongly denounced the Russian occupation” of Crimea.

Spicer told reporters that President Trump has made it clear to Russia that he expects it to “de-escalate the situation” with Ukraine, and to "return Crimea" to Ukrainian sovereignty.