The votes were nonbinding, but the leaders of the neighboring regions hope to leverage strong turnout in talks with Italy's center-left government. As leading members of the anti-migrant, anti-EU Northern League, they want to keep more tax revenue and have autonomy over such policy areas as immigration, security, education and environment.

"This is the big bang of institutional reform," Veneto President Luca Zaia said in Venice. "We are convinced, and I hope Rome understands, that this is not the wish of a political party. These are the wishes of the people."

In Milan, his counterpart in Lombardy, Roberto Maroni, said that with the votes, the two regions "can unify our forces so we can do the battle of the century."

The two leaders say they will meet with their regional councils to finalize their requests before going to Rome to meet with Premier Paolo Gentiloni.