WASHINGTON, JULY 24 (AP/UNB) – The D.C. Public Schools are firing 241 teachers and warning more than 700 other employees that they could be fired in the next year if their performance doesn't improve.

The firings announced Friday total 302 school system employees, including the 241 teachers. They come largely as a result of the first year of a new teacher evaluation system, though 76 teachers were fired for problems with their licenses.

The evaluation is based largely on five classroom observations of teachers and their students' standardized test scores. Those found "ineffective" on a four-tier system were fired.

Washington Teachers' Union President George Parker says the union will challenge the firings for performance.