Ukraine's special forces inflicted millions of pounds worth of damage on Putin's army in another devastating drone attack.

While operating in the Sumy direction, SSO operatives spotted a BUK M1 air defence system, which was preparing to fire a missile.

The special forces unit quickly targeted the BUK 1, wiping it out in a clinical strike. Video posted by Ukraine's army shows the moment a kamikaze drone smashes into the BUK, which explodes into a ball of flames.

Thick black and white smoke spiralled upwards as missiles in the BUK's launcher explode. Further footage shows Russian soldiers desperately trying to douse the fire as the Ukrainian observation drone hovers above.

In a statement Ukraine's Armed Forces said: "Operators hit targets with strike drones. The occupiers tried in vain to put out the fire and save the equipment.

"As a result of the strike, a launch-loading installation with six missiles was destroyed, and the firing installation of the BUK-M1 complex was damaged."

A BUK 1 air defence system is thought to cost around US$100 million (£80m). Its missiles have a 34 km maximum range and can travel at a top speed of 1,200 m/s.

It is designed to destroy strategic and tactical aircraft, cruise missiles, helicopters, and other aerial objects.

The BUK can be used for air defence of troops, military facilities, important administrative-industrial areas, and other zones during mass air attack scenarios.

It can also serve as a module of an integrated tactical anti-missile defence network.

A BUK was involved in the downing of a Malaysian passenger airliner flying over eastern Ukraine in 2014.

The plane was shot down by Russian separatists and all 283 passengers and 15 crew died in the tragic incident.

The Joint Investigation Team set up to investigate the crash concluded the MH17 was shot down by a BUK missile from the 9M38 series.

The missile was launched by a BUK TELAR installation that was transported from the Russian Federation to a farm field near Pervomaiskyi in Eastern Ukraine.

At that time, that area was controlled by the separatists. After firing, the installation was transported back to the Russian Federation with a missing missile.