A new outside spending group is launching an ad buy supporting Republican Gabriel Gomez's Senate campaign in Massachusetts.

A source affiliated with the group, Americans for Progressive Action, confirmed to The Hill that its going up with a "significant buy" in Massachusetts this week.

The Washington Post is reporting that the buy amounts to about $700,000, enough to air an ad for about a week in the state.

Little is known about the group aside from its treasurer, listed on forms filed earlier this month, as Nancy Watkins, who also appears to have served as treasurer for Rep. Michele BachmannMichele Marie BachmannTom Petty dies at 66 Bachmann: Muslim immigrants trying to undermine Western civilization Religious leaders pray over Trump in Oval Office MORE's (R-Minn.) presidential campaign.

Democratic Senatorial Campaign Committee Executive Director Matt Canter noted the connection to Bachmann in a statement on the buy.

"The fact that Michelle Bachman's campaign treasurer is spending $700,000 to support Gabriel Gomez tells Massachusetts voters everything they need to know about the kind of Republican policies Gomez would support in the US Senate," he said.

But APA spokeswoman Sheena Tahilramani said the group isn't conservative, and instead will support candidates with an "independent streak."

"Americans for Progressive Action is focused on having a positive impact on elections in America by supporting and promoting candidates that represent a better future for America. We believe that this will include people with a more independent streak who care more about doing what is right, than relying on partisan politics," she said in an email.

Tahilramani wouldn't elaborate on whether the group would be willing to spend to support Democrats in future races. But in Massachusetts, she said the group is spending there to back what they view as a "moderate, reasonable candidate."

"In Massachusetts, we saw a moderate, reasonable candidate with very little outside help who was being outspent by Democrats 3 to 1. Gabriel Gomez is a great American—an American hero—and we want him to have the opportunity to make his case to the people of Massachusetts," she said.

Tahilramani formerly worked as chief of staff and media liaison to prominent conservative strategist Karl Rove, the Republican behind the prominent GOP super PAC American Crossroads. She now leads the marketing team at PR firm 7 Second Strategies.

Gomez remains the underdog in the race to replace Secretary of State John KerryJohn Forbes KerryFor the sake of national security, Trump must honor the Iran deal Bernie Sanders’s 1960s worldview makes bad foreign policy DiCaprio: History will ‘vilify’ Trump for not fighting climate change MORE (D), as Rep. Edward MarkeyEdward (Ed) John MarkeyDems lambaste Trump’s ‘outrageous’ EPA chemical safety pick Dems plan to make gun control an issue in Nevada Dem senator pitches ideas for gun control after shooting MORE (D-Mass.) has led him in every poll of the race. But Gomez has kept that lead down to single-digits, stirring Democratic worries that Markey could suffer an upset similar to the one that sent Republican Scott Brown to the Senate during the 2010 special election.

Democrats have sent a number of heavy-hitters to the state to campaign for Markey, culminating in a Wednesday visit from President Obama.

The Democratic Senatorial Campaign Committee and Senate Majority PAC also recently went up with significant ad buys attacking Gomez. But until this group launched its own buy, no outside group had invested in the race for Gomez, waiting for clear evidence he could pull off an upset.

--This post was updated at 8:02 p.m. to correct the partisan afiliation of the group.