Outside spending in the Massachusetts special election has topped $1.25 million, with most of the cash going to support Rep. Edward MarkeyEd MarkeyOPINION | Shailene Woodley: US should run on renewable energy by 2050 Dems urge 'transparent and inclusive' nuke policy review Senate confirms former Boeing VP as deputy Defense secretary MORE's (D-Mass.) bid for the Democratic nomination.

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An analysis of Federal Election Commission filings reveals that nearly $970,000 has been spent by outside groups supporting Markey, while one group, affiliated with the International Association of Firefighters, has spent $85,000 to support Markey's Democratic primary rival, Rep. Stephen Lynch (D-Mass.).

The $1.25 million figure was first reported by the Associated Press.

Two groups — NARAL Pro-Choice America and NextGen Committee, a super PAC backed by billionaire Tom Steyer — have spent more than $208,000 opposing Lynch.

The League of Conservation Voters, which has endorsed Markey, has spent more than $556,000 so far to help elect him to the Senate seat vacated by Secretary of State John KerryJohn KerrySenators who have felt McCain's wrath talk of their respect for him Dems see huge field emerging to take on Trump Budowsky: Dems need council of war MORE (D). The group has pledged to spend at least $650,000 to support him.

No outside groups have yet spent for any of the three Republican candidates in the race, though one Tea Party group is planning on launching radio and television ads for Mike Sullivan, a former George W. Bush official who is considered the frontrunner in the GOP primary.

The outside spending comes even as both Markey and Lynch have signed a pledge to keep such money out of the race. The "Peoples' Pledge," which originated in the race between Sen. Elizabeth WarrenElizabeth WarrenSanders keeping door open on 2020 Scaramucci deletes old tweets bashing Trump Trump's new communications chief once called him a 'hack' MORE (D) and former Sen. Scott Brown (R), bars outside groups from launching ads on television, radio or online in support of -- or opposition to --- a candidate in the race.

But a handful of groups have found loopholes in the pledge, and continue to pump funds into the race — efforts that, due to the shortened timeline and low turnout expected for a special election, could notably impact the results.

Canvassing, sending informational mailers to a group's members and polling are all beyond the scope of the pledge.

And at least one group, Steyer's NextGen Committee, has flouted the pledge, launching an online petition drive highlighting Lynch's support for the Keystone XL pipeline. Both candidates say that drive violates the pledge. Though Markey and Lynch have expressly asked him to stay out of the race, Steyer has refused to pull back his efforts.

The candidates have just three weeks until the April 30 primary, and the Democratic nominee is expected to win the seat in the general election.