DENVER (Reuters) - Thousands of Denver public school teachers will walk the picket lines for a third day on Wednesday, disrupting classes for about 92,000 students after union and school district officials ended talks with no deal in sight, union officials said.

In the latest strike in a series to hit U.S. public school systems, the 5,650-member Denver Classroom Teachers Association seeks higher pay with a salary structure focused less on performance bonuses and more on cost-of-living increases.

The Denver labor dispute follows statewide teacher walkouts last year in Arizona, Kentucky, Oklahoma and West Virginia, and a six-day strike in Los Angeles settled last month with a deal to cut class sizes and raise salaries by 6 percent.

Talks in Denver broke down on Saturday, triggering the first walkout by teachers in Colorado’s largest city since 1994.

The two sides returned to the bargaining table on Tuesday, but late in the day a DCTA spokesman said talks had ended for the night and would resume at 10 a.m. Wednesday. He declined to comment on whether a deal was close.

No representative of the school district was immediately available to comment.

The Denver Public Schools district has said its latest proposal would raise teachers’ pay by nearly 11 percent next year, while the union has called that figure inflated.

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On Monday, Public Schools Superintendent Susana Cordova told reporters the district had already met many of the teachers’ demands for simplifying their complicated pay structure.

“We’ve made really significant changes already,” Cordova said. “Many of the things I think that we hear our teachers complain about, actually aren’t about the proposal that we’ve put on the table, it’s about the current system. And many of those things I agree with as well.”

District officials vowed to keep all 207 schools open through the strike, staffed by substitute teachers and administration personnel. But on Tuesday the district said it canceled pre-kindergarten classes.

The so-called ProComp pay system at the crux of the strike was embraced by the union when it was instituted in 2005, touted as a way for teachers to build their salaries through a mix of possible incentives.

Those include bonuses tied to student achievement and tougher teaching assignments, such as schools in high-poverty areas.

But the union says ProComp, one of the longest-running teacher pay schemes of its kind in the country, has instead eroded teacher pay in a city where the cost of living has soared in the past 10 years.

Denver Mayor Michael Hancock on Monday expressed support for the teachers’ pay demands and offered to help mediate the dispute.