Oakland teachers say they will strike starting Thursday.

The union representing the 3,000 teachers announced the walkout Saturday, making it the latest in a wave of educator activism that has swept the U.S. since last spring.

The union wants smaller class sizes, more counselors and full-time nurses, and a 12 percent raise over three years. The district has offered 5 percent and says it is squeezed by rising costs.

The action comes a day after the sides received compromise recommendations in a fact-finding report.

Oakland Unified School District Superintendent Kyla Johnson-Trammell said Friday she was pleased with the recommendations and hoped it would coax the union back to negotiations.

"If both sides are committed to settling the contract before a strike occurs -- and we are -- an agreement can certainly be reached without disrupting the educational experience for students, families and staff," she said in a statement Saturday.

But union president Keith Brown said the teachers will strike unless the district dramatically changes its spending approach.

"We will strike for our students, we will strike for education justice, we will strike for racial justice," Brown said at a news conference Saturday. "We will strike for the future of public education in Oakland."

Oakland Unified has about 37,000 students.

The city of roughly 400,000 is preparing for a strike, although Mayor Libby Schaaf is urging both sides to continue negotiating. The city is opening recreation centers and all public libraries for families affected by a strike.

The strike would follow one by Denver teachers, who ended a three-day walkout this week after reaching a tentative deal raising their wages. Teachers in the nation's second-largest school district, Los Angeles, staged a six-day strike last month. That walkout ended when teachers settled on a 6 percent raise and promises of smaller class sizes and the addition of more nurses and counselors.