OAKDALE, Minn. (AP) — Minnesota Gov. Mark Dayton is expressing his strongest support yet for an expansion of the famed Mayo Clinic that depends on the state aiding with related development costs.

Dayton told a group of veteran Democrats at a luncheon Monday that he sees room for negotiation on what a public contribution would be. But he says he’s “absolutely certain” the state needs to step up in some form to help one of its largest private employers.

Mayo says it will proceed with a multibillion-dollar expansion of its Rochester campus if it can get a state commitment. Clinic leaders say more than $500 million in public money is essential for infrastructure upgrades. The center’s proposal would divert a slice of future tax dollars to pay for roads, sewer work and the like.

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