PORTLAND (AP) — New York Mayor Michael Bloomberg, who’s already donated a half-million dollars to Maine independent Angus King’s U.S. Senate campaign, will host a fundraiser for the former governor, prompting fed-up Democrat Cynthia Dill to proclaim the out-of-state spending on the race “repugnant.”

Bloomberg, also an independent, donated $500,000 to Americans Elect, which used it to help buy $1.75 million worth of ads on King’s behalf. The expense followed an outlay of millions of dollars by the U.S. Chamber of Commerce, National Republican Senatorial Committee and another so-called super PAC on behalf of Republican Charlie Summers’ bid for the Senate seat being vacated by Olympia Snowe.

Dill, who is losing the fundraising battle against King and Summers, lashed out in frustration over Bloomberg and his donation.

“It seems to me the seat is perceived to be for sale, and that is repugnant to me,” she said Thursday, a day after she issued a statement calling for Summers and King “to end the financial arms race in Maine.”

King’s campaign has accused the GOP and conservative groups of starting the exorbitant television advertising wars. Meanwhile, Republicans are calling King hypocritical for decrying the influence of outside money, while accepting contributions from people outside Maine like Bloomberg. The Bloomberghosted fundraiser will be held Tuesday in New York.

The amount of spending has grown swiftly since Mainers saw the first attack ads during the Olympics, when the Chamber of Commerce attacked King as “king of spending” and “king of mismanagement.” A Republicanled super PAC followed with ads aimed at drawing votes from King by urging Democrats to stick with Dill.

The Republican National Senatorial Committee weighed in with more attacks on King. Then the Democratic Senatorial Campaign Committee, which hasn’t issued an endorsement, finally weighed in by attacking Summers, leaving one to wonder whether the ads were aimed at supporting Dill or King, himself a former Democrat.

All told, outside spending has topped $4 million so far.

Amy Fried, political science professor at the University of Maine, said she can understand Dill’s frustration during an election cycle in which so much out-of-state money is flowing into Maine.

“We’re in a new era in our post-Citizens United world where a lot of outside money is going to flow in,” she said, referencing the U.S. Supreme Court ruling allowing unlimited outside expenditures by super PACs.

Dill, a working mom who says she best reflects the values of working-class families, attacked the spending as outsized in a rural state where she said one in five children have inadequate food and 15 percent of Maine families live in poverty.

“The campaign fundraising has gotten recklessly out of control,” she said. “In a state where frugality is prized and a $40,000 wage still supports a family, this financial arms race must end now.”

Kay Rand, King’s campaign manager, said King’s proposal in June to limit expenditures made by outside organizations if all three candidates agreed to it was rejected by Summers.

But she suggested that the money is necessary to counter attacks on King, and she pointed out that Americans Elect’s donors are publicized.