For those in Ukraine who live along the border with Russia the hostility between the two countries has split families and friends.
The second biggest city Kharkiv sits just half an hours drive from the border.
Many in the city speak Russian as their first language and previously pro-Russian sentiment was strong.
But since the intervention in the east and the annexation of Crimea in 2014, allegiances have shifted. If President Putin did decide to invade this would probably be his first stop, so what kind of reception would his soldiers receive?
Our international editor Lindsey Hilsum went to find out.