Gov. Mark Dayton called the Vikings' opposition to possible Major League Soccer games at U.S. Bank Stadium "sour grapes" because the team's owners lost an expansion franchise to a rival group led by former UnitedHealth Group CEO Bill McGuire.

Dayton made the comments at a Capitol news conference even though he wasn't specifically questioned about the disagreement between the Vikings and the Minnesota Sports Facilities Authority (MSFA) over who has the right to make a deal for Minnesota United to play in the new building.

The Vikings say the legislation and the use agreement for the building give them that exclusive right for five years. Michele Kelm-Helgen, MSFA chairwoman who was appointed by Dayton, disagrees and said she has had discussions with Minnesota United about playing a single game in the $1.1 billion building.

Who would get the money should Minnesota United play at U.S. Bank Stadium would need to be negotiated.

But comments from two years ago appeared to support the Vikings position. Kelm-Helgen told the Star Tribune in March 2015 that she told the McGuire group that Vikings owners Mark and Zygi Wilf have an exclusive five-year window regarding soccer at the stadium. "No other owner of a Major League Soccer team could play there unless the legislation is changed." McGuire had been told that previously, she said at the time.

But Kelm-Helgen said she has been consistent that no other team can "establish" a MLS team in the stadium and play a whole season. She maintained Wednesday that the MSFA is free to negotiate a single game, possibly in early 2017.

The Vikings do not agree. "We're not saying they can't or shouldn't play at U.S. Bank Stadium," said Lester Bagley, team vice president. "We're saying they can't do so without our consent. Regarding the MSFA, we would expect they'd honor our agreement."

The feud was revealed late last week.

The governor turned up the public heat Wednesday, saying he was "shocked" by the Vikings position. "This is not the Vikings' stadium," he added. "This is the people of Minnesota's stadium. It's run by the stadium authority for the people's benefit which means generating opportunities for Minnesotans to come together and support the various opportunities they enjoy."

The Vikings are the main tenant in the stadium and paid $609 million of the cost to build it, adding enhancements that would make it amenable for indoor soccer. The taxpayers covered the remaining $498 million of the cost.

The soccer disagreement comes as the MSFA faces public criticism and an investigation by the legislative auditor over its use of two free luxury suites at the stadium.

Until Minnesota United has its own stadium, the team plans to play at TCF Bank Stadium at the University of Minnesota.

Dayton told reporters that United was "talking about playing a select number of games" at U.S. Bank Stadium.

Bagley said that, for the Vikings, having a say in soccer is "a matter of principle, protecting our investment and enforcing our rights."

Rochelle Olson • 612-673-1747

Twitter: @rochelleolson