Three men were arrested in a series of raids that targeted an online protection racket that threatened to crash Web sites unless the gang was paid off. More arrests are expected to follow.
The gangs were targeting online betting firms around the world, including several big UK names.
Earlier this year one UK bookmaker, who wished to remain anonymous, said his firm had been attacked several times. The gangs would typically contact the online firms through a customer-service email address on the Web site with a demand for between £10,000 and £30,000 as well as a warning that if it wasn't paid then a distributed denial of service (DDoS) attack would be launched against the site during peak traffic hours.
The bookie said all the UK firms had refused to pay the ransom and had been working with the NHTCU to combat the attacks, but admitted the cost of putting extra IT security measures in place was as much as £100,000 for some firms.
Blue Square was one of the firms that publicly admitted to being targeted after its site was taken down by blackmailers flooding it with a DDoS attack.
Betfair also revealed last month that during Euro 2004 it was hit by a DDoS attack that caused disruption to its service.
The NHTCU wouldn't say which Web sites the three men were suspected of targeting. A NHTCU spokeswoman suggested that the joint operation with the Russian police had some way to run.
"It's a case of shaking the tree and seeing what happens," she said.