Citigroup CEO Jane Fraser announced the company was carrying out its next layer of management changes in a sweeping reorganization, according to a memo to staff on Monday.

“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,” Fraser said in a separate statement.

Specific leadership changes across businesses and functions will be communicated by executives on Monday first to their teams and later posted on an internal site, the memo to employees said.

As part of the reshuffle, the US bank will name one of its most senior bankers in Europe, Nacho Gutiérrez-Orrantia, new head of banking in the region, according to people familiar with the situation.

In his new role of head of the Europe cluster, the Spanish banker will look after Citi´s businesses in Europe.

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

In the memo, Fraser said the final announcements related to the overhaul will happen at the beginning of 2024.

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.

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

Support staff in compliance and risk management, and technology staff working on overlapping functions are at risk of being laid off, Reuters reported in September.