Citigroup Inc plans to cut at least 2,000 jobs starting next month as the lender restructures its businesses, Bloomberg reported.

A substantial portion of the layoffs will be in middle or back-office positions, Bloomberg reported, citing a person briefed on the matter.

Citigroup declined to comment.

The bank, due to report fourth-quarter earnings on Jan. 15, had 239,000 employees as of the end of September.

Citigroup said this month it would take a $300 million "repositioning charge" in the quarter to "resize infrastructure and capacity" throughout its businesses.

Like other U.S. banks, Citigroup too has been hurt by weak oil prices due to exposure to loans to oil companies.