A tentative settlement has been reached in the week-old Cleveland teachers' strike, a federal mediator said today. ``I'm happy to say that the School Board and the Cleveland Federation of Teachers reached a tentative agreement and will be reporting back to their respective constituencies,'' Jack Buettner said late this morning. ``The parties will then review the details of the proposal at that time.'' Details of the agreement were not disclosed, pending a ratification vote. Superintendent Al Tutela declined to comment on when schools might re-open for the district's nearly 73,000 students. Eugene Kolach, president of the 5,100-member teachers union, said union negotiators will recommend to the union's executive committee that the tentative agreement be approved. Early this morning, members of the Cleveland School Board said they believed progress was being made toward ending the strike. On Tuesday, Craig Brown, chief negotator for the school board, had said talks seemed to be snagged on the issue of ``career ladder,'' a plan to hinge some pay raises largely on performance evaluations. The union's contract expired in September. Teaching salaries range from $17,600 to $37,450, depending on education and experience. The average teacher makes $29,000 annually. Tutela said the district's 2,951 non-teaching school employees, such as maintenance workers and janitors, were being laid off this week. The layoffs were to continue during the strike, he said.