Aug 31 (Reuters) - Citigroup Inc has told senior staff in Europe that they would receive fixed monthly pay in addition to their salaries in an attempt to compensate for rules that limit bonuses to up to twice the level of base salaries, the Financial Times reported, citing several people.

More than 600 of Citigroup bankers in Europe were affected by the bonus cap and will therefore be paid such allowances, several people told the newspaper. (http://on.ft.com/Z3H47g)

They said the U.S. bank had sent out letters to senior staff in recent weeks.

The FT said about half of the bankers had received similar allowances in the past after Citi introduced them a few years ago to mitigate the impact of regulatory demands for higher bonus deferrals for key staff.

One senior Citi banker told the FT the allowances had been structured so that the bank's European staff would still receive the same amount of overall pay and a similar mixture of cash and shares as their U.S. and Asian peers.

"We do not want people to have geographic preferences based on compensation," the banker told the FT.

In June, Dutch state-owned bank ABN AMRO increased the salaries of 100 top managers by 20 percent to compensate for new regulations on bonuses cap in the Netherlands.

Citigroup could not be reached for a comment outside of normal business hours.

(Reporting by Aashika Jain in Bangalore; Editing by Sandra Maler)