A 10,000-signature petition against the potential closure of half of Sheffield's libraries has been handed in at the city's town hall.
The city council said the service's budget is being cut by £1.6m, and up to 14 libraries will close unless they are taken over by businesses or volunteers.
The signatures have been collected by Liberal Democrat councillors.
Councillor Shaffaq Mohammed said there was "anger across Sheffield" at the Labour-run authority's plans.
"We've put forward a number of sensible suggestions which would allow the council to avoid the closure of a single library.
"Unfortunately, these have been rejected by Labour bosses who are determined to protect their own pet projects."
But Labour councillor Mazher Iqbal said: "We have to find these savings of £1.6m. No council service has been immune from cuts."
The authority has invited organisations interested in running libraries to come forward before 8 April.
"We don't want to see any libraries close. Individual organisations have come forward. We've had a very good response," Mr Iqbal added.
He said 6,000 people had responded to a consultation on the future of the library service last year, and most respondents thought "developing partnerships with others was a good idea".
There are 28 libraries in Sheffield with 184,000 registered users.