Hackers caused a major traffic jam in Moscow after exploiting the ride-hailing app, Yandex taxi, to summon dozens of taxis to the same location at the same time. The attack occurred on September 1st and had traffic heading towards kutuzovsky prospect – an already busy Boulevard – stuck at a standstill.

A video showing lines of taxis trying to get to the same destination was shared widely on Twitter and Reddit. Moscow ranked number two as the world’s most congested city in the world last year.

The ride-hailing service, owned by the Russian Internet giant, Yandex, said that the jam lasted about 40 minutes. Yandex did n’t immediately respond to the verge’s request for comment.