The US Embassy has issued a warning to US citizens in Moscow about a possible terrorist attack in Russia's capital.
They went on to caution Americans to have an evacuation plan ready in the case of an emergency.
The Embassy said: "There have been threats of attacks against shopping centres, railway and metro stations, and other public gathering places in major urban areas, including Moscow and St. Petersburg as well as in areas of heightened tension along the Russian border with Ukraine,"
They added Americans should “review their personal security plans” and have escape plans that “do not rely on US government assistance”.
This comes as the US has intelligence that Russian commanders have received orders to go ahead with an invasion of Ukraine.
According to CBS News, officials from the country have said that Russian commanders on the ground are making specific battle plans for how they would deal with an invasion of the country.
This does not mean an invasion is guaranteed, as Russin President Vladimir Putin could change his mind, the official stressed.
These threats come after weeks of warnings that an invasion is coming or of cyber attacks and false flag operations from Russia and their allies.
Speaking to ‘Face the Nation’, US Secretary of State Anthony Blinken said: "Everything we're seeing tells us that the decision we believe President Putin has made to invade is moving forward.
"We've seen that with provocations created by the Russians or separatist forces over the weekend, false flag operations, now the news just this morning that the 'exercises' Russia was engaged in Belarus with 30,000 Russian forces that were supposed to end this weekend will now continue because of tensions in eastern Ukraine, tensions created by Russia and the separatist forces it backs there."
Russia has amassed as many as 150,000 soldiers on the border and claimed many of these troops were conducting military drills.
Moscow previously said they were due to finish this Sunday until the Belarusian defence minister announced the drills would be extended.
Amidst this, life continues largely as normal in Ukraine, although a number of citizens have taken up drills with Ukraine’s Territorial Defence Force.
The crisis on the border has been brewing since 2014, and for years the conflict has been ongoing between the Ukrainian government and pro-Russian rebels backed by Moscow.
The rebels have claimed a number of self-proclaimed republics in the eastern part of the country and seized control of the city of Donetsk under the so-called Donetsk People's Republic.