Drone raids help Kyiv carry the fight deep into Russia

Last week, a motorist driving in Russia's Leningrad region came across something unusual. Men had blocked off the road. In front, a large olive-green military vehicle with cigar-shaped missiles on the back was reversing and then parked up on a snowy verge. "Fuck! It's an S-300," the driver exclaimed, before adding: "So guys, let's prepare for the worst."

- Luke Harding and Pjotr Sauer

This surreal roadside encounter took place outside St Petersburg, more than 1,000km from the border with Ukraine and Russia's near two-year all-out war. The Kremlin's security services were apparently taking no chances. They were deploying the S-300 air defence missile system in order to protect Peter the Great's imperial capital from drone attacks.

So far this year, Ukrainian drones have struck at least four Russian oil and gas terminals across the country. The attacks are part of a growing asymmetrical campaign by Kyiv to cripple the industry and to deprive Moscow of the billions of dollars in global revenue it uses to fund its war. About half of Russia's $420bn export earnings last year came from oil.

"Russia finances its military from oil exports. You can't persuade countries like India and China to stop buying it. So you knock out Russian oil refineries," said Illia Ponomarenko, a former defence reporter for the Kyiv Independent newspaper.