One of the most iconic machine guns ever made is the Soviet-built DShK – known as the Dushka.
It has been used in wars from Vietnam to Syria and an adapted version is being used by the Ukrainian military.
The Dushka was originally developed in the 1930s as an anti-aircraft gun and can fire 600 rounds a minute at a range of 1.5 miles.
Ukraine inherited thousands of Dushkas when the Soviet Union collapsed, and they then removed them from vehicles and modified them into infantry support weapons.
The Ukrainian weapon is fitted with a large muzzle brake to dampen the recoil as well as a pistol grip and shoulder stock to let the firer get close to the ground.
A bipod helps to stabilise the weapon when firing.
The Ukrainian weapon is particularly useful in trench warfare.
Just two infantrymen are required to operate the Ukrainian Dushka and when used with a scope or an observer it is highly accurate against targets up to 500m away.