British Prime Minister Boris Johnson said on Tuesday Russia appeared to be planning a full-scale invasion of Ukraine, warning that if the Kremlin goes ahead with it, President Vladimir Putin would be forced to face his catastrophic miscalculations.

After chairing a meeting of the UK’s national emergency security committee, Johnson spoke to reporters, “I think the tragedy of the present situation is that President Putin has surrounded himself with like-minded advisors who tell him that Ukraine is not a proper country. And, I think that he is going to find that he has gravely miscalculated.”

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Johnson also stated that the United Kingdom will implement tough economic measures on Russia right away. Putin ordered soldiers to be deployed in two breakaway regions of eastern Ukraine, prompting the British Prime Minister’s comments.

“This is, I should stress, just the first barrage of UK economic sanctions against Russia because we expect I’m afraid that there is more Russian irrational behaviour to come,” Johnson said.

These economic penalties, according to the British Prime Minister, would not just target entities in Donbas, Luhansk, and Donetsk, but also Russia’s commercial interests.

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Other European leaders, in addition to Johnson, have enacted or are considering enacting penalties against Russia.

“We are going to implement appropriate and targeted sanctions against Russian interests with our European partners,” Bruno Le Maire, the French finance minister said on Tuesday.

Italy’s foreign minister, Luigi Di Maio, stated that his administration is certain that sanctions should be implemented.

European Union leaders have begun meeting to consider measures against Russia, which will go beyond individual travel bans and asset freezes.

Meanwhile, Russian Foreign Minister Sergei Lavrov has retaliated, claiming that Moscow is used to sanctions, which are imposed for a variety of reasons.

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Last week’s apparent halt to Russia’s invasion of Ukraine has turned into the greatest crisis in East-West relations since the Cold War. On three sides of Ukraine, up to 150,000 Russian troops are stationed.

Russian armoured vehicles have also been observed moving across separatist-controlled territory, according to reports. Moscow has yet to confirm the presence of troops in the rebel agencies.

According to the Associated Press, Vladislav Brig, a member of the separatist local council in Donetsk, told reporters that Russian troops had already gone in, taking up positions in the region’s north and west.