The disturbing satellite images: What is Russia doing?

About 35,000 Russian personnel are located permanently near Ukrainian territory. On Wednesday, the Russian Defence Ministry published photographs of military units on their way to a training centre in Rostov, near the Ukrainian border.

Some newcomers have traveled nearly 4,000 miles from the Far Russian East, writes the BBC. Most estimates say the number of Russian troops deployed around Ukraine in the north, south and east of the country is about 100,000. But a Ukrainian assessment, published by CNN, says there are 106,000 ground troops and 21,000 Navy and Air Force members.

British Prime Minister Boris Johnson said Tuesday:

“Intelligence services are very clear that there are 60 Russian combat groups on the Ukrainian borders, about a third of the total available”.

In addition to regular Russian troops, it is estimated that there are about 150,000 Russian separatists in the Ukraine regions of Luhansk and Donetsk.

But some Western analysts say Russia has not yet collected everything needed for an earthly invasion. They highlight the lack of mobile hospitals on the ground with full personnel in some areas. The arrival of the medical staff, they say, can show readiness for an attack.

Russian forces of several thousand soldiers have been transferred to Belarus for a joint military exercise that will reach a peak between 10 February and 20 February. President Alexander Lukashenko has backed Russian President Vladimir Putin.

Ukraine's capital, Kiev, is less than 60 miles [100 km] from the Belarus border. Western observers say the exercise, called Allied Resolve, could provide an opportunity to practice a mission against Ukraine.

Photos posted on the internet reportedly show military equipment, including armoured vehicles, tanks and missile systems, travelling towards the area. Russia has announced the deployment of advanced Su-35 fighter aircraft in Belarus, along with air protection systems, ammunition and medical support.

Russia is also conducting global sea exercises -- from Atlantic to Pacific -- from this month to February, in which 140 ships and support ships, 60 planes and 10,000 people are participating.

Six Russian Navy ships, capable of landing the main battle tanks, personnel and armoured vehicles, crossed the English Channel on their way to the Mediterranean exercises. But it is unclear whether the Black Sea and the Ukrainian coast may be their real destination.

Some analysts say the amphibious landing of Russian troops would be extremely difficult and that the sea forces could be a “masquerading” to draw the attention of Ukraine's ground forces from the most likely roads of attack on land.