PHILADELPHIA (AP) _ The city and its striking teachers reached a tentative agreement on a new contract before dawn Monday, allowing classes to proceed at the nation's seventh-largest school district.

The city and Philadelphia Federation of Teachers had worked since Sunday afternoon to try to end the first teachers' strike in nearly two decades before it idled more than 210,000 students heading to classes Monday.

``Schools will be open, buses will be running, and teachers will be in their classrooms _ and we hope to be as close to business as usual today as possible,'' Mayor John F. Street said Monday.

Teachers went on strike at the end of the school day Friday after failing to reach a contract agreement. Their union represents 21,000 teachers, nurses, librarians, counselors and other school employees at 260 district schools.

``We are very pleased that we were able to reach a contract settlement and we are asking all members to report on time and perform their regularly scheduled duties,'' teachers union president Ted Kirsch said. He said a ratification meeting would be scheduled as soon as possible.

Street and Kirsch refused to discuss the details of the tentative contract.

The impasse came down to the length of the school day. The mayor had been seeking a 45-minute increase in the current 6 1/2-hour workday, a reduction from the one-hour increase he originally sought. The teachers had offered a one-half hour increase.

When talks stalled last month, Street unilaterally imposed new work rules, including the one-hour increase to begin next year and a 18.1-percent raise over five years. Union leaders said teachers already put in plenty of extra time and wouldn't be forced to stay at school without extra pay.

Gov. Tom Ridge stood behind the mayor, and had expressed support for a state takeover of the school system if Street requested it. Such a move would have allowed the state to revoke the credentials of any teacher who remains on strike.

Some also feared that a strike by Philadelphia's teachers could disrupt the Nov. 7 election and damage Vice President Al Gore's chances of winning Pennsylvania. If the teachers decided to picket the 198 schools that serve as polling places, voters in the heavily Democratic but strong labor city might have stayed home rather than cross the lines.

The last teachers strike in Philadelphia lasted 51 days in 1981.

___

On the Net:

Philadelphia schools: http://www.philsch.k12.pa.us

Philadelphia Federation of Teachers: http://www.pft.org