Russian police conducting an arrest (FILE PHOTO). REUTERS/Tatyana Makeyeva Russia arrested about 50 people allegedly involved in a hacking ring that had stolen more than $25 million from financial institutions inside the country.

Russia's Federal Security Service (FSB) and Interior Ministry carried out nationwide raids which, in addition to the arrests, resulted in the seizure of computer and communications equipment, financial documents, and large sums of cash.

The hacker group allegedly stole money from various banks with malicious software called Lurk, which infected the computers of people who visited infected websites, giving the hackers access to their bank credentials.

They also apparently gained direct access to some of the systems of the banks targeted.

Cybersecurity firm Kaspersky Lab helped identify the perpetrators before they could make off with an additional $35 million.

“Our company’s experts analyzed the malicious software and identified the hacker’s network of computers and servers," Ruslan Stoyanov, head of computer incidents investigation at Kaspersky Lab, said in a statement. "Armed with that knowledge the Russian Police could identify suspects and gather evidence of the crimes that had been committed. We look forward to helping to bring more cybercriminals to justice."

At least six banks were targeted, including Metropol, Regnum, Russian International Bank, and Metallinvestbank, the latter of which alone saw more than $10 million stolen, according to TASS.