CLEVELAND, Ohio -- Democratic presidential candidate Bernie Sanders took to Twitter Wednesday evening to support Cleveland Public Library union workers locked in a labor dispute with library management.

About 400 librarians, library assistants and custodians, represented by the represented by Service Employees International Union District 1199, have been without a contract since the end of the year. After months of negotiations, the workers said Wednesday they plan to go on strike on Feb. 4 at noon if a deal can’t be reached.

The workers have said their central concern is ensuring the library system is properly staffed and safe. The library system said the main hang-up centers around wages.

Sanders said the library workers “deserve adequate staffing and safe working conditions.”

Public libraries are essential to our communities. The workers who provide these vital services deserve adequate staffing and safe working conditions. I'm proud to stand in solidarity with the members of @seiu1199wvkyoh as they fight for a fair contract. https://t.co/eMAe4VpNN9 — Bernie Sanders (@BernieSanders) January 23, 2020

The library system and the workers have planned to sit down at the negotiating table one more time today. The next dates on the calendar are after the potential strike. Talks have been ongoing since September.

The library is also negotiating with its security workers, who have also been without a contract since the end of the year. Those talks remain on-going.

Read more on this issue:

Library workers to strike Feb. 4 if deal can’t be reached

Cleveland Public Library criticized for message on union dispute

Cleveland Public Library workers give union the OK to strike, if agreement cannot be reached

Cleveland Public Library workers consider strike authorization vote