CHICAGO (CBS) — A northwest suburban school board has urged teachers to return to work on Thursday, after more than a week on strike.

Prospect Heights School District 23’s board said it made its best and final contract offer to teachers at 12:40 a.m. Wednesday, and has asked the 150 striking teachers and support staff to vote on the offer Wednesday, so students can return to class Thursday.

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Wednesday already had been a scheduled day off for the more than 1,500 students at the four schools in District 23.

Teachers have been on strike since last Wednesday.

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It’s unclear whether the teachers’ union will take a vote on the district’s latest offer.

On Monday, the board offered teachers a four-year deal, with most teachers getting 3.25 percent raises in each of the first three years, and 3 percent in the fourth year.

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The teachers have been seeking a 3-year deal with pay raises of more than 4 percent per year.