Story highlights Trump had previously buoyed Russia's claim to Crimea

Kremlin insists 'Crimea is part of the Russian Federation'

(CNN) US President Donald Trump has taken a swipe at the previous Obama administration, suggesting it was "too soft" on Russia over its annexation of Crimea.

Under increasing pressure over his administration's relationship with Russia , President Trump commented on Twitter Wednesday that the Crimea peninsula was "taken" by Russia from Ukraine under the Obama administration.

Crimea was TAKEN by Russia during the Obama Administration. Was Obama too soft on Russia? — Donald J. Trump (@realDonaldTrump) February 15, 2017

The comments mark a sharp U-turn for Trump, who had previously buoyed the Kremlin's claim on Crimea.

Russia annexed Crimea, a territory in the former Soviet republic of Ukraine, in March 2014 following tensions with its neighbor.

The White House and the Kremlin have engaged in back-and-forth commentry over Crimea in recent days. Trump's Press Secretary Sean Spicer said Tuesday: "President Trump has made it very clear that he expects the Russian government to deescalate violence in the Ukraine and return Crimea."