PORTLAND — A nonpartisan group that tried unsuccessfully to draft a candidate to run for president said Friday it plans to spend more than $1 million on TV ads supporting independent Angus King in the state’s U.S. Senate race, the only race it intends to get involved with during the current election cycle.

The first of two ads sponsored by Americans Elect went into rotation on Friday and will be joined by another ad touting King’s independence during a two-week campaign, spokeswoman Ileana Wachtel said.

“At this moment, it is critical that we elect independent-minded leaders to high office,” she said. “Angus King running for U.S. Senate in Maine is that kind of leader, and Americans Elect is supporting him.”

A spokesman for Republican Charlie Summers, the beneficiary of more than $2 million in outside spending on TV ads in the campaign, accused King of flip-flopping after his early criticism of outside money.

But King’s spokeswoman, Crystal Canney, said the Republican National Senatorial Committee started the ad wars and it’s too late to stop the out-of-state spending in the high-stakes race for the seat being vacated by Olympia Snowe, who’s retiring.

“We will not unilaterally disarm,” Canney said. “The time has passed when this money could have been kept out of Maine. We don’t like it and wish we could have worked together with the candidates to attempt to prevent it. You can thank the NRSC and Charlie Summers for turning this into an ad war.”

King, a former two-term governor, and Summers, the secretary of state, are in a fierce contest to replace Snowe, a Republican. Also in the race are Democratic state Sen. Cynthia Dill and three other independents, Steve Woods, Andrew Ian Dodge and Danny Dalton.

King entered the race with a commanding lead, but the race has tightened with King enduring attacks that started over the summer.

The TV campaign by Americans Elect praises King’s political independence and talks about the need for independents to break the partisan gridlock in Congress. In the first ad, the narrator says, “Here in Maine, people aren’t looking for Democratic jobs or Republican jobs. We just need jobs.”

“Electing independent candidates to the U.S. Senate is crucial,” Wachtel said. “An independent caucus operating in the Senate can do a lot to break down the historical levels of political gridlock and partisanship dominating Washington today.”

Americans Elect was dedicated to finding an independent presidential candidate through online caucuses, but it abandoned the process in May. It previously said it would not be endorsing candidates.

Wachtel declined to get into specifics about how the group went about its decision to endorse King’s candidacy but said it wasn’t getting involved in other races.

Independent Eliot Cutler, King’s campaign chairman and a former gubernatorial candidate, used to sit on the board of Americans Elect but gave up the post in June.

The Maine GOP, citing Cutler’s involvement with the group and King’s campaign, said Friday it was seeking a Federal Elections Commission investigation into whether there were illegal coordinated communications between the organization and the campaign.