A rift has developed between Truro City Council and Cornwall Council over library opening hours.
The city council has asked for a reconsideration of proposals to close Truro Community Library on Saturday afternoons.
Saturday is the busiest day for the library and staff said the closure would also damage other services such as adult education and the Citizen’s Advice Bureau.
Cornwall Council is consulting with staff across the county on reducing opening hours to cut costs.
The letter from Roger Gazzard, clerk at Truro City Council, said councillors had resolved to object to the Saturday afternoon closure.
The letter said: “The Council requests that you reconsider this proposal and allow the library to continue at the current opening hours.”