A suspicious package addressed to Deutsche Bank chief Josef Ackermann contained a fully functional bomb, German authorities say.
The bomb was intercepted after a routine X-ray screening yesterday in the mailroom of the bank's Frankfurt headquarters.
Experts deactivated the bomb but the authorities refused to give any further details because of a continuing investigation.
The New York Police Department said it had been alerted and sent patrols to the bank's offices in the city "solely as a precaution".
A spokesman said the return address on the letter was the European Central Bank - the governing body for the eurozone, which has its headquarters just across the park from Deutsche Bank in Frankfurt.
The Swiss-born Ackermann, 63, was awarded a negative prize by an anti-lobby group yesterday for allegedly cutting deals with German Chancellor Angela Merkel regarding efforts earlier this year to save Greece from bankruptcy.
Deutsche Bank rejected the charges.