London police arrested eight men in connection to a 1.3 million pound ($2.1 million) computer-aided robbery from a Barclays Plc branch in the capital.

The money was taken from the Swiss Cottage branch via the bank's computer system in April, the Metropolitan Police said in a statement today. Barclays has recovered a "significant amount" of the stolen funds, police said.

The men, who are between 24 and 47, were arrested yesterday and today and are in custody in a London police station. Searches are being carried out at addresses across London where cash, jewelery, drugs and credit cards have been found.

It's the second time in a week that London police announced arrests over suspected bank hacking. The Met said on Sept. 13 it detained twelve men over an attempt to hack into Banco Santander SA computers, preventing a theft potentially worth millions of pounds.

Banks face cyber-security threats from increasingly sophisticated hackers trying to steal customer identities or access funds. Andy Haldane, executive director for financial stability at the Bank of England, told lawmakers in June that regulators should "take a close look at the state of preparedness" of major banks to protect against cyber-attacks.

In the Barclays case, police said a man posing as an information technology engineer had installed a device in the local branch that allowed the group to remotely transfer money to accounts.

"Barclays has no higher priority than the protection and security of our customers against the actions of would-be fraudsters," Alex Grant, a managing director for fraud prevention at the bank, said in a statement. "We can confirm that no customers suffered financial loss as a result of this action."