The FBI has offered temporary security clearances to officers from financial institutions in order to share information into repeated cyber attacks with US banks which have disrupted online banking websites in recent months.

Bank security officers were invited to a classified video conference held at 40 FBI field offices around the country, according to FBI Executive Assistant Director Richard McFeely.

The video conference offered insight into “who was behind the keyboards,” according to McFeely, speaking to at the Reuters Cybersecurity Summit.

Customer accounts have not been put at risk by the attacks – although the sustained DDoS attacks have meant it has been impossible to access bank websites. One NBC report claimed that the websites of 15 major banks were offline for a total of 249 hours in six weeks earlier this year.

Earlier this year President Barack Obama signed an executive order to improve information-sharing between companies and branches of government, saying, “"We cannot look back years from now and wonder why we did nothing in the face of real threats to our security and our economy."

Banks such as Wells Fargo and Bank of America were first attacked in September 2012, by a group calling itself Izz ad-Din al-Qassam Cyber Fighters. The attacks have continued since then. McFeely declined to discuss who was behind the attacks, or other details of the continuing investigation.

McFeely said that the one-day security clearances are part of an effort to communicate more effectively with victims of cybercrime, admitting that the agency had been “terrible” in the past. “That’s 180 degrees from where we are now,” McFeely said.

McFeely said, “"The first time we bring someone in from out of the country in handcuffs, that's going to be a big deal.”