By Jim Finkle

(Reuters) - The U.S. Federal Bureau of Investigation last month urged banks to look for signs of possible cyber attacks in the wake of the massive heist at Bangladesh's central bank, asking them to hunt for technical clues that they have been targeted by the same group.

The private "Flash" notification, which provided technical information about the attacks, said a "malicious cyber group" had compromised the networks of multiple foreign banks.

"The actors have exploited vulnerabilities in the internal environments of the banks and initiated unauthorized monetary transfers over an international payment messaging system," the alert said.

The report did not identify specific victims. An FBI representative declined to elaborate on the report.