BOSTON (AP) — Millions in campaign cash are flooding into Massachusetts in the final days of the race to fill the late Edward M. Kennedy's Senate seat, funding an all-out ad war between Democrat Martha Coakley and Republican Scott Brown.

Voters can't turn on a television or radio without being deluged by appeals on behalf of Brown or Coakley — or, more often, sharply worded attack ads.

Neither campaign would detail how much it has raised since Jan. 1, and disclosure laws make it hard to come up with firm, up-to-date numbers. But the figure easily reached into the millions in just the past week, according to a review of the fundraising numbers the candidates have confirmed combined with expenditures by interest groups.

"Money has poured in unlike anything I've seen in a one-week period in the history of Massachusetts," said Paul Watanabe, a political science professor at the University of Massachusetts. "This is money that Martha Coakley didn't expect that she would have to raise and this is money that Scott Brown thought he couldn't raise."

The race changed when polls suggested Brown, considered a long shot, was closing on Coakley. Conservative groups sensed a chance to quash President Obama's agenda and hand a defeat to Senate Majority Leader Harry Reid, D-Nev.

Brown, who had just $367,150 in his campaign account on Jan. 1, pulled in $1.3 million in a 24-hour online blitz last week.

A range of advocacy groups is also backing Brown, from the U.S. Chamber of Commerce, which has spent $500,000 on a television campaign, to the Tea Party movement, which has spent $200,000.

"The reason we're endorsing Scott Brown is that his vote would be critical to defeating Harry Reid's health care plan which the Tea Party movement is universally opposed to," said Tea Party Express spokesman Levi Russell.

Others have zeroed in on Brown's promise to be the "41st vote" against the health care bill. The legislation needs 60 votes to advance in the 100-member Senate.

Americans for Responsible Health Care is spending $200,000 on two TV spots calling Brown "the nation's best last chance to stop this harmful legislation." The Iowa-based conservative advocacy group American Future Fund has spent about $600,000 on an ad asserting Coakley "supports the reckless spending by Washington politicians."

"Thanks to a tremendous outpouring of grass-roots support, we have the ability to pay our bills and get our message out," said Felix Browne, a spokesman for Brown's campaign.

Coakley, who had nearly $1 million in her account on Jan. 1 after a four-way primary battle, has been buoyed by appeals on her behalf by Obama and Kennedy's widow, Vicki Kennedy. The campaign said the Vicki Kennedy appeal raised about $700,000 in a day.

Coakley also benefited from a Washington fundraiser attended in part by health care industry lobbyists.

Like Brown's, Coakley's campaign is being aided by outside groups.

EMILY's List, which supports female candidates who back abortion rights, is spending about $250,000 on a radio ad it says highlights Brown's record of voting with the Republican leadership.