Don’t be fooled by the wacky names like “Music Hall,” ‘’Happy Guys” or “Aliens”, highly-trained Russian hooligan groups are as nasty as they come and tune up for ultra-violence on a regular diet of pre-arranged fights throughout their domestic season and — whenever they can — in Europe.

Viciousness and organization are the hallmarks of these “firms”, who have put aside their domestic rivalries at the European Championship. With the exception of Polish hooligans, they are the most consistently violent around. Last weekend, Marseille’s southern seaport was turned into a battle ground, as they launched coordinated attacks against English supporters in the old port area before and after Saturday’s European Championship match.

They were “like grasshoppers that destroy everything and leave,” Bruno Trani, who represents the CRS riot police in the Marseille region for the Alliance police union, said in a phone interview with The Associated Press, estimating their numbers at up to 250.

“When you see a compact group moving together, slam into a group of English people and then move away again in a group you can tell that they are organized,” Trani added. “(They) left no chance to the English who were drunk andtired by alcohol and the sun.”

This week all eyes will be on chillier northern France, but it remains to be seen whether tensions have cooled.

Russia plays Slovakia in Lille on Wednesday, and England faces Wales the next day in Lens in cities just 30 kilometers (20 miles) apart — raising the prospect of more clashes. Trains from England stop in Lille.

What also stood out during last weekend’s melees was the differing fighting styles, revealing the degree to which the Russian hooligans prepare.