Jim Finkle, reporting for Reuters:SWIFT, the global financial messaging system, on Tuesday disclosed new hacking attacks on its member banks as it pressured them to comply with security procedures instituted after February's high-profile $81 million heist at Bangladesh Bank. In a private letter to clients, SWIFT said that new cyber-theft attempts -- some of them successful -- have surfaced since June, when it last updated customers on a string of attacks discovered after the attack on the Bangladesh central bank. "Customers' environments have been compromised, and subsequent attempts (were) made to send fraudulent payment instructions," according to a copy of the letter reviewed by Reuters. "The threat is persistent, adaptive and sophisticated - and it is here to stay." The disclosure suggests that cyber thieves may have ramped up their efforts following the Bangladesh Bank heist, and that they specifically targeted banks with lax security procedures for SWIFT-enabled transfers. The Brussels-based firm, a member-owned cooperative, indicated in Tuesday's letter that some victims in the new attacks lost money, but did not say how much was taken or how many of the attempted hacks succeeded.