Merrill Lynch has confirmed at least one death among its ranks from the attack on the World Trade Center.

A note from Merrill’s CEO David Komansky and president Stanley O’Neal reveals that three of the firm’s employees remain unaccounted for, and one “has tentatively been identified as deceased.” Merrill says as it gets more information it will pass it along to employees and investors.

Merrill Lynch employees joined in an interfaith memorial service conducted at 12:00 ET at its Princeton corporate campus. The service was broadcast on an audio conference call.

As well, Merrill Lynch ran a memorial ad in 14 major U.S. and international newspapers today, remembering the victims, praising the bravery of the public safety officers who are working so hard to save lives, and expressing confidence in the strength of Merrill Lynch and the resilience of the global financial system.

There are indications of potential structural problems with the American Express tower adjacent to Merrill Lynch’s North and South Towers. This situation is being actively investigated and it is planning for alternative work sites.

“It may be a matter of several months before we can contemplate reoccupying the North Tower and even longer for the South Tower. Fortunately, we have significant capacity at other locations in New York and New Jersey and are actively planning for their utilization. As specific information is finalized about alternative work sites, your manager will inform you. Please be patient, as it will take some time to finalize plans for all of our people.”

As the markets reopen, Merrill Lynch expects to resume all business activities through the alternative arrangements that it has put in place. “Once again, we appreciate your hard work, dedication and teamwork during this extraordinary period. It is inspiring.”