Russia may invade Ukraine, warns U.S.

The United States has warned European allies that Russia could be plotting to invade Ukraine in a repeat of the 2014 annexation of Crimea.

U.S. officials have privately briefed EU counterparts on a possible military operation as tens of thousands of Russian troops amass near the border.

Senior Whitehall sources said the Government was concerned about the reports and that there was “twitchiness” and “anxiety” among officials.

It came amid heightened tensions as Vladimir Putin, the Russian president, was accused of orchestrating a migration crisis on the border between Belarus and Poland to destabilize Europe.

On Thursday the Kremlin claimed that it had scrambled a fighter jet to intercept a British spy plane operating in the Black Sea region.

Meanwhile, Russian forces, including elite troops, are gathering near the Ukraine border, with some deployed covertly at night.

The invasion assessments are believed to be based on U.S. intelligence not yet shared with Europe, multiple sources told Bloomberg.

U.S. president Joe Biden discussed the Ukraine situation with Ursula von der Leyen, the European Commission president, at the White House on Wednesday, and Kamala Harris, the U.S. vice-president, met with Emmanuel Macron, the French president, in Paris this week.

Last week, Biden dispatched William Burns, the CIA director and former U.S. ambassador to Russia, to Moscow where he spoke with Putin by phone and conveyed the Biden's concerns.

U.S. officials warned Moscow against making a “serious mistake” amid its buildup of troops. They have shared intelligence on the Russian movements with allies, and briefed them on the possibility of a military operation. The U.S. also said its commitment to Ukraine's security was “ironclad.”

The Kremlin has denied it is an aggressor and has accused the U.S. and NATO of provocation. Putin repeated that message Thursday in a call with Angela Merkel, the German Chancellor.

Russia's defence ministry claimed the incident involving a British Boeing RC-135 Rivet Joint reconnaissance plane was part of a wider uptick in military activity by the U.S. and its allies. It said the Russian military scrambled a Sukhoi SU-30 fighter jet to intercept, and that the British plane changed course away from Crimea.

“The Russian Defence Ministry treats the military activity of the U.S. and its allies in the Black Sea region as scouting out a potential theatre of war in case Ukraine prepares a military operation to solve the crisis in eastern Ukraine,” said Maj. Gen. Igor Konashenkov.

Ukraine's defence ministry has said about 90,000 Russian troops are stationed not far from the border.