ECOWAS will not send an election observer mission to the country, the group said in a statement that is a rare expression of pre-election criticism of a member state.
President Yahya Jammeh is widely expected to secure another term at the helm of country he has run since a 1994 coup. Gambia is popular with tourists for its tropical beaches but is regularly criticised for its rights record and press muzzling.
The ECOWAS statement said a fact-finding mission had found “intimidation, an unacceptable level of control of the electronic media by the party in power … and an opposition and electorate cowed by repression and intimidation”.
The commission said it had informed Jammeh that it would not send an observer mission “because the preparations and political environment … are adjudged by the Commission not to be conducive for the conduct of free, fair and transparent polls”.
The statement said that ECOWAS remained ready to work with Gambia to “create a level playing field for future elections”.
After years of criticism for being a toothless body, ECOWAS has in recent years taken a stronger stance against coups and flawed elections, especially in Niger, Guinea and Ivory Coast.
Jammeh is due to face two challengers in the vote but there has been little sign of opposition campaigning in the run-up to the vote and analysts say few voters have faith in the process.