NEW YORK: A top Citigroup (C.N) executive asked employees to speak up if they see inappropriate behavior after a managing director sued the company this week, alleging she was sexually harassed by a manager in equities.

"No colleague should ever be discriminated against or harassed," Andy Morton, Citigroup's global head of markets, wrote in the memo sent on Tuesday, which referenced a recently filed lawsuit. "We will take decisive action when we determine unacceptable behavior has taken place."

Managing director Ardith Lindsey sued the bank in New York, saying it downplayed her complaints about Mani Singh, who had been North America Markets head of cash equity execution services before he resigned last November.

Lindsey accused Citigroup of tolerating a "notoriously hostile" environment in its equities division and said Singh subjected her to sexual harassment and abuse, including death threats.

Requests for comment made to a lawyer who represented Singh in an unrelated lawsuit were not immediately answered.

Citigroup said in an earlier statement that it will defend against Lindsey's claims.

"Part of everyone's role in creating a culture of the highest standards involves stepping in at the moment we see something wrong," Morton wrote. "If you experience or witness inappropriate behavior, you can raise your concerns through official channels without fear of retaliation," including with managers, human resources or the company's ethics hotline.