The United States has advised its citizens to immediately leave Ukraine and Belarus amid mounting tensions with Russia, the Associated Press reported.

The U.S. embassy in Ukraine said in a statement on Monday that American citizens should depart the country immediately using commercial or other privately available transportation options.

“The security situation in Ukraine continues to be unpredictable due to the increased threats of Russian military action. Conditions may deteriorate with little notice,” the U.S. embassy in Kyiv said.

Meanwhile, the U.S. Department of State also issued a Level 4 “do not travel” advisory for Belarus and Moldova due to the concerning Russian military buildup and troop movements in the region.

It said U.S. citizens in Moldova’s breakaway region of Transnistria should depart immediately via commercial or private means.

Russia has been building up its forces near Ukraine, with well over 100,000 troops lined along the border, and has sent troops to exercises in neighbouring Belarus.

CBS News reported on Monday that Russian troops are currently leaving their assembly points and moving into “attack positions” — the latest escalation in Russia’s ongoing aggression towards Ukraine.

On Friday, U.S. President Joe Biden’s national security adviser, Jake Sullivan, warned that U.S. intelligence shows a Russian invasion could begin within days. The U.S. picked up intelligence that Russia is looking at Wednesday as a target date, according to a U.S. official familiar with the findings.

But Russia denies it intends to invade Ukraine.

Ukrainian President Volodymyr Zelenskyy has also played down invasion concerns, urging the country to remain calm.

As the tensions escalate in the region, the Canadian military announced on Sunday it’s in the process of temporarily relocating members of its Joint Task Force – Ukraine (JTF-U) to elsewhere in Europe.

On Saturday, Canada shuttered its embassy in the Ukrainian capital of Kyiv and relocated its diplomatic staff to a temporary office in Lviv in the western part of the country.

The United States is also relocating its Ukraine embassy operations to Lviv, Secretary of State Antony Blinken said on Monday, citing a “dramatic acceleration in the buildup of Russian forces.”

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