DENVER (Reuters) - Public school teachers in Denver overwhelmingly voted late Tuesday to go on strike to press their demands for more money and incentive pay, after negotiations with Colorado’s largest school district hit an impasse last week.

Having failed to reach a settlement after 15 months of talks, 93 percent of the 3,500 members of the city’s largest union, Denver Classroom Teachers Association, voted to authorize their first strike in 25 years.

“They’re striking for better pay, they’re striking for our profession, they’re striking for Denver students,” union spokesman Rob Gould said.

In all, the district employs 5,650 teachers. Unless a last-minute deal is reached, the strike could begin on Monday.

The strike vote came on the same day that teachers ratified a contract deal with the Los Angeles Unified School District, the country’s second-largest school district, to end a week-long walkout. The settlement provided a 6 percent pay raise as well as a plan to hire more nurses and other support staff at the district’s more than 1,200 schools.

Denver Public Schools Superintendent Susana Cordova has vowed to keep the district’s 207 schools open during the labor dispute using substitute teachers and administrators. There are more than 92,000 students enrolled in the district.

Cordova said the district offered teachers a 10 percent increase in pay for the 2019-2020 school year, among other incentives.

“We came to the table to bargain in good faith and offered proposal after proposal – adding $26.5 million and responded to structural concerns – in an attempt to reach an agreement,” Cordova said in a written statement.

But union leaders said the district’s offer provides no incentives for longtime educators to earn raises while the union proposal rewards teachers for advancing their education during their careers.

“They have refused to change their ways, choosing to keep an outrageous amount of money in administration rather than keep our teachers in school,” said union president Henry Roman, referring to district administrators. The two sides remain $8 million apart, he said.

In Chicago on Wednesday, representatives from the Chicago Teachers Union held a news conference outside the monthly meeting of the city’s board of education to repeat demands by teachers in their own contract negotiations. The union said the demands echoed what was secured in Los Angeles.

“In Los Angeles, they got a nurse in every school,” Chris Geovanis, a union spokeswoman, said in a telephone interview. “In Chicago, we have a nurse for every five schools if we’re lucky.”

If Denver educators do go on strike, it would be the first teachers’ strike in the city since a five-day walkout in 1994. Cordova said she will ask for the state labor board to intervene this week in an effort to break the stalemate.

Denver is the latest school district to face labor troubles with its teachers in the past year. In 2018, teachers staged walkouts over salaries and school funding in several states, including West Virginia, Oklahoma and Arizona.

Teachers in Oakland, California, were also expected to vote later this week on whether to strike.