NEW YORK - Citigroup CEO Jane Fraser and top executives announced the next layer of leadership changes as part of a sweeping reorganization on Monday, according to memos to staff seen by Reuters and sources familiar with the situation.

"The actions we're taking to reorganize the firm involve some difficult, consequential decisions, but we believe they are the right steps to align our structure with our strategy," the bank said in a separate statement.

Senior leaders held calls on Monday to explain the new structure and role changes in each division, according to a source familiar with the situation who declined to be identified discussing personnel matters.

Citi announced plans to cut management layers from 13 to eight as part of its biggest overhaul in decades. In the top two layers of leadership, Citi reduced 15% of functional roles and eliminated 60 committees, it said in a third-quarter earnings presentation.

Memos seen by Reuters outline management changes in its wealth, investment banking and consumer units.

Citigroup declined to comment on all the personnel moves, and none of the leaders named responded to requests for comment.

Eduardo Martinez Campos, head of Citi Wealth Services, is leaving after more than three decades at the bank, according to a memo from Andy Sieg, Citi's new head of wealth.

Valentin Valderrabano will continue to serve as the wealth unit's chief operating officer, and Patricia Dorosz will move to a new client division to serve as chief administrative officer. Sieg will discuss the changes with his group on Dec. 5.

In investment banking, Nacho Gutiérrez-Orrantia will become banking and cluster head for Europe, according to a separate memo. Several country officers are leaving their roles. Carmen Haddad, who ran Saudi Arabia, is moving into the client organization as a vice chair. Fahad Aldeweesh will succeed Haddad. Jose Miguel Salvador Nasur will oversee banking in Chile.

"Our pipeline remains strong, and we expect activity to consistently pick up across M&A and capital markets," wrote Peter Babej, interim head of banking, and Ernesto Torres Cantú, head of international, in the memo.

In the U.S. personal banking division, Brad Wayman was appointed as chief operating officer, and some roles were merged, according to a separate memo. Chris McCullough was appointed to succeed Wayman as head of mortgage and small business lending, while Patrick Gallagher was picked to lead execution. Two other executives are leaving.

The research team led by Lucy Baldwin will move from markets to a newly created client organization, another memo showed. Sandeep Arora will oversee digital platforms for institutional clients in the group. The bank is recruiting for a chief marketing and officer.

The full reorganization could involve thousands of layoffs, according to a source familiar with the situation who was not authorized to speak publicly.

Preparations for Monday's announcements were communicated verbally in meetings last week, according to another source familiar with the situation. Some staff may be able to apply for other roles at the bank, the source said.

Final announcements related to the overhaul will be made early next year, Fraser said in a memo to employees. Mark Mason, the bank's finance chief, will likely discuss the impact of the changes in fourth quarter results in January.

(Reporting by Tatiana Bautzer and Lananh Nguyen in New York and Andres Gonzalez in London; Additional reporting by Saeed Azhar, Svea Herbst-Bayliss, Echo Wang and Isla Binnie; Editing by Nick Zieminski, Stephen Coates and Marguerita Choy)