YOBS torched vans and cars in an overnight rampage - with Royal Mail vans among the vehicles targeted.
Cops are now hunting the culprits after the attacks across Tower Hamlets, east London, in the early hours of Wednesday morning.
Cops rushed to Royal Mail's Docklands Delivery Office just before 3am, after three vans were torched at the site.
That same night, three more vans and three cars were set alight on nearby streets.
Police are treating the incidents as suspicious, with the culprits still on the loose.
It is also believed that an Openreach van on Salmon Lane was damaged in what a source described as an "arson attack" on Wednesday 8 February.
Royal Mail was unable to comment as the incidents are now a police matter.
A spokesman for the Metropolitan Police said: "We are investigating a series of vehicle fires in Tower Hamlets.
"At this time, the incidents are being treated as suspicious and enquiries remain ongoing.
"Anyone with information that could assist police is asked to call 101 or tweet @MetCC and quote ref 4204313/23.
"Alternatively, contact the independent charity Crimestoppers anonymously on 0800 555 111."
Pictures shared on social media showed a red Royal Mail van at the Docklands depot with the driver's window smashed and the interior melted by fire.
A worker at the depot said: "We've had four vans melted in total, one about a week or two ago while it was out on delivery and three more today.
"There was also some weird spray painting. No idea who did it."
A spokesman for the London Fire Brigade said: "I can confirm that we received multiple calls overnight about several vehicle fires in the Limehouse area."
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