ABC News' Michael Falcone reports:

Both the Obama campaign and the Romney campaign are now on the air in Minnesota - a state that has been rated as a solidly Democratic, but where reliable public polling is hard to come by.

As of Friday, the Obama campaign had placed a $511,000 television ad buy on broadcast stations in Minneapolis for twelve days - Oct. 27 through Nov. 6 - according to a source tracking spending on the airwaves.

This is the first buy Obama has placed on Minnesota broadcast channels for the general election. Last week Team Obama reportedly purchased $57,000 worth of airtime on cable in the Minneapolis market and on Duluth radio.

Notably, the Minneapolis market bleeds into several counties in the tossup state of Wisconsin.

This news comes on the heels of the Romney campaign's own ad buy in the Minneapolis-St. Paul media market from Saturday through next Tuesday, Oct. 30. Ad tracking sources say that buy amounted to $30,000 and marks the first time Romney has placed ads in Minnesota during the general election.

A pro-Romney super PAC, American Future Fund, reported spending roughly $1.6 million in the state of Minnesota since September. Earlier this month the group also released a polling memo in the state calling the race there "a dead heat."

And the Republican National Committee sent out a note Friday evening, reminding everyone that as of May 2012, Obama campaign manager Jim Messina put Minnesota in the "safe state" category.