The West African force deployed to The Gambia last month to help President Adama Barrow take power will be cut to 500 from 7,000 this month.
A statement from Mr Barrow’s office read on state television said the gradual scaling down would begin no later than 19 February, Reuters news agency reports.
The troops intervened when long-time ruler Yahya Jammeh refused to leave power after losing elections in December.
Regional leaders had to threaten to remove him by force to end to the crisis.
Mr Jammeh agreed to go into exile in Equatorial Guinea only after thousands of foreign troops entered the small West African country.
The 500-strong force left behind will have a three-month mandate to protect Mr Barrow and other government members.
Sections of Gambia’s security services were under Mr Jammeh’s personal control.
Mr Barrow also announced that the National Intelligence Agency (NIA), the notorious secret police which had “instilled fear amongst citizens”, would be reformed, AFP news agency reports.
Its name would change and functions would be limited to “intelligence gathering, analysis and advice to the relevant arms of government responsible for internal and external security”.
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