Ontario's elementary school teachers could be on strike as of May 10.

Negotiations between the Elementary School Teachers' Federation and the province broke down and the union asked for a "no board report," which puts them in a legal strike position in 17 days.

The union says the Liberal government's demands would "strip ETFO members' collective agreements, erode their working conditions and reduce teachers' ability to use their professional judgment."

The union says this doesn't mean negotiations have ended, and it is open to meaningful bargaining.

This is the first round of negotiations since the Liberals brought in a new bargaining system, with both local and provincial talks -- monetary issues are being handled centrally.

Local talks are not going well with high school teachers at several boards, with one on strike, another set to go out Monday and a third with a May 4 strike date.

High school teachers in Rainbow District, which encompasses Sudbury and the surrounding area, will go on strike Monday if the board is unable to reach a deal with teachers over the weekend.

One more day of bargaining with a mediator is scheduled for Saturday, but the president of the Ontario Secondary School Teachers' Federation local said he's not confident they'll get a local deal with one more day of talks.

"I must say my optimism is at an all-time low with regard to the way that the school board has gone through this whole process of bargaining thus far," said James Clyke. "It's been pretty lethargic."

Clyke said two of the major issues locally are professional judgment and the "incursion" of the school board and the ministry into classrooms and working conditions for teachers.

Monday was already scheduled to be a professional activity day in the Rainbow District. The board said parents should look for updates on its website for what will happen Tuesday, but if there is a strike, schools will be closed for 5,500 students.

"I remain optimistic," said board chair Doreen Dewar. "We're very committed to reaching a local negotiated settlement and we're going to cling to that hope until we find out differently."

High school teachers in Durham Region went on strike April 20, leaving 24,000 students out of class. High school teachers in Peel Region have set a strike date of May 4.