After days of promising a veto, Gov. Mark Dayton on Thursday formally rejected the education budget bill because of the lack of funds for universal prekindergarten, among other priorities.

Dayton said the $17.1 billion education bill the Legislature approved Monday did not fund his top priority of access to preschool for all of the state's 4-year-olds. It also did not provide funding for the elimination of a Head Start waiting list, additional funding for the Northside Achievement Zone and the St. Paul Promise Neighborhood.

Dayton will be calling legislators back for a special session, likely not before early June. If no agreement is reached on public schools funding, state officials warn that the Department of Education would be shut down, causing mass layoffs.

House Education Finance Committee chairwoman Jenifer Loon, R-Eden Prairie, issued a statement expressing disappointment at the veto.

"Our education budget was the picture of bipartisanship — where both sides came together to do what is right for our youngest Minnesotans," Loon said. "I am disappointed that Governor Dayton is forcing a special session over an education bill that garnered such strong support from both sides of the aisle and made a significant financial commitment to our students."

Dayton will meet with House GOP leadership on Tuesday to begin negotiations over the pending special session. The DFL governor said Wednesday that the scope of the special session will be narrow, and he hasn't yet indicated whether he might veto other budget bills.