The White House has called a Russian convoy's move into Ukraine a "flagrant violation" of the country's sovereignty and urged Russia to remove it or face more economic sanctions.
White House deputy national security Ben Rhodes told reporters that sending the convoy into Ukraine adds to the escalation of the conflict "in a dangerous way."
The United States plans to discuss the situation with the UN Security Council later today, he added.
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"Our own president uses words infamously spoken by Josef Stalin to describe his enemies," Senator Jeff Flake said.
The Met Office has issued a fresh amber warning of heavy snow for southern Scotland and northern England on Wednesday into Thursday.
Speaking from the backbenches, the former education secretary said future MPs could "improve or undo" what is implemented.