TORONTO -- Ontario's public elementary school teachers returned to the bargaining table Monday on the first day of a work-to-rule strike -- only to walk away again.

During their job action schools will remain open and extracurricular activities and field trips continue for now, but teachers won't administer standardized tests, add comments to report cards or participate in any professional development related to Ministry of Education initiatives.

Premier Kathleen Wynne said during question period Monday that talks between the province and the Elementary Teachers' Federation of Ontario had resumed, but they broke down again less than half an hour later.

"It was our expectation that the government and the Ontario Public School Board Association would remove concessions from the table," union president Sam Hammond said in a statement. "That did not happen and the meeting ended at 11 a.m."

Education Minister Liz Sandals said she hopes that with a mediator's support the two sides will be able to make progress.

She is, however, worried about high school students in three boards where teachers are on strike, she said.

East of Toronto, 24,000 students have been kept from class by a strike at Durham Region high schools since April 20. In Sudbury and the surrounding area, 5,500 students have been out of school since April 27 by a strike at Rainbow District high schools. West of Toronto, 42,000 students are not in class because of a strike by high school teachers in Peel Region.

"Each of the boards actually does have web-based course material that's been posted on the board website," Sandals said. "There hasn't been a lot of traffic on those websites and I'm getting concerned that perhaps parents and students don't realize the material is there."

An Education Relations Commission is responsible for deciding whether students' school year is in jeopardy has not yet received any requests for such rulings from any of those boards, Sandals said.

Central talks are stalled, but the three boards do have a few dates of local talks scheduled.

In Durham, the union president said "very little progress" was made during one day of talks with the board on Friday.

"This really does feel like brinkmanship bargaining," said Dave Barrowclough. "They're only interested in talking about their issues...Doesn't matter if it's something with no dollar value attached to it, they're not interested in talking about (our issues)."

This is the first round of negotiations for both high school and elementary teachers since the province brought in a new bargaining system with both local and provincial talks. Sandals has said it may be difficult for local deals to be reached before there are central agreements, which is why she is urging all parties to be at the bargaining table.