Story highlights Russia's declaration comes ahead of first meeting between top diplomats

Statement follows reports of Trump campaign advisers' constant contact with Russia

(CNN) Russia's Foreign Ministry has indicated that it intends to keep Crimea and not return it to Ukraine because it considers it to be part of Russia.

Russia's Foreign Ministry spokeswoman Maria Zakharova told reporters Wednesday during a weekly news conference: "We're not returning our territory. Crimea is part of the Russian Federation."

White House Press Secretary Sean Spicer said Tuesday that Trump had been taking a tough line with Russia and that he expected Moscow to withdraw from the region, which it occupied following a " full-scale invasion " in 2014.

Spicer pointed to UN Ambassador Nikki Haley's recent remarks on Russia's actions in east Ukraine and occupation of Crimea, adding that Trump "expects the Russian government to de-escalate violence in the Ukraine and return Crimea."

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The Ministry's declaration comes as it emerged that high-level advisers close to then-presidential nominee Donald Trump were in constant communication during the campaign with Russians known to US intelligence, multiple current and former intelligence, law enforcement and administration officials tell CNN.