Ukraine war: Satellite images reveal Russian defences before major assault

A beach resort bristling with fortifications. A major road lined with anti-tank ditches. Satellite analysis by BBC Verify has uncovered some of the extensive defences built by Russia as it prepares for a major Ukrainian counter-attack.

After months of stalemate, the expected assault is likely to be a crucial test for Ukraine as it seeks to prove it can achieve significant battlefield gains with the weapons it has received from the West.

By examining hundreds of satellite images, the BBC has identified some key points in the significant build-up of trenches and other fortifications in southern Ukraine since October.

These four locations offer an insight into what Russia expects from the counter-offensive, and what defences Ukrainian forces might encounter.

1. Crimea's west coast

Seized by Russia in 2014, Crimea was formerly known for its beach resorts.

Now, instead of sun loungers and parasols, the coastline stretching for 15 miles (25km) is littered with defence structures installed by Russian troops.

The image below shows the only open sandy beach on the west coast without natural defences such as cliffs or hills.

Firstly, there are "dragon's teeth" along the shore: pyramid-shaped blocks of concrete, designed to block the path of tanks and other military vehicles.

Behind them is a line of trenches, providing cover from incoming attacks. Several bunkers can also be spotted along the trenches.

Stacks of wood, digging machines and stores of dragon's teeth along the coast suggest building work was still in progress when the image was taken in March.

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Some military experts suggest the defences are likely to be a precaution, rather than a sign that Russia expects to defend a seaborne assault, since Ukraine has little naval capacity.

Intelligence analyst Layla Guest says: "The fortifications are likely in place to deter any bold Ukrainian operation to attack Crimea via the sea rather than on land."

The beach fortification is just one example of a vast network of trenches, as shown by the black dots in the map below, based on work by open-source analyst Brady Africk.