Although talks continued late, Chicago Public Schools officials say schools will be closed a fourth day due to a teachers strike.
School officials made the announcement late Wednesday.
Chicago Teachers Union President Karen Lewis is expressing concern that after a contract is reached, the district plans to close up to 100 schools.
During a break in contact talks, Lewis said that plan is a sticking point in negotiations. She said the closings will lead to thousands of experienced and dedicated teachers being replaced and "actually having their careers destroyed."
School officials haven't denied underutilized schools will be closed. Chicago Mayor Rahm Emanuel said Wednesday it hasn't been decided how many will be shut.
The strike of Chicago teachers has kept more than 350,000 students out of class. About 50,000 charter school students are in school.