UPDATED: April 9, 2012 at 8:56 p.m.

Harvard Law School professor Elizabeth Warren announced Monday that her campaign for U.S. Senate raised $6.9 million in the first three months 2012—the largest single-quarter total seen thus far in the high-profile Massachusetts race and more than double the amount raised in the same time by her Republican opponent, Senator Scott Brown.

For the third consecutive quarter, Warren outpaced Brown, who raised a more modest $3.4 million in the first three months of this year. Warren saw a moderate increase from the final quarter of 2011, when she raised $5.7 million.

“The incredible enthusiasm we have seen from people across the Commonwealth who are contributing to this campaign shows the strong grassroots momentum behind Elizabeth’s fight for middle class families,” Warren campaign manager Mindy Myers wrote in a statement.

Political analysts said that Warren’s totals are impressive and indicate that her campaign has attracted unusually high levels of attention.

“That’s a big number, especially for a fist time candidate,” Democratic consultant Daniel B. Payne said. “It demonstrates that a lot of politically aware people believe she’s credible and that Scott Brown is vulnerable.”

But the gains were not enough for the first-time candidate to catch up with Brown, who has been bolstered by leftover funds from his 2010 campaign. Brown currently has roughly $15 million in his campaign till, while Warren’s camp has brought in roughly $12 million.

“Scott Brown still has $4 million more in the bank than we do, but this is the kind of support we need to be able to take on the big banks and corporations that are lining up against Elizabeth,” Myers wrote.

Both Warren and Brown have emphasized the grassroots, local nature of their campaigns.

Warren announced last week that her campaign had raised $2.5 million from 30,000 donors in Massachusetts. Eighty-three percent of those donations were $50 or less, and the donors came from 350 of the 351 cities and towns in the Bay State.

However, nearly twice as much, $4.4 million, of Warren’s first-quarter intake came from out of state. The consumer advocate and former Congressional adviser has fostered a great deal of enthusiasm among Democratic heavyweights around the country, and in Hollywood in particular, who have helped line her campaign coffers.

Republicans have criticized Warren’s financial support from outside Massachusetts, calling her hypocritical and out of touch with the common voter.

“Professor Warren’s fundraising continues to be mostly out-of-state money from extremely liberal donors and special interests that are trying to influence the Massachusetts election,” Brown spokesman Colin Reed wrote in an email.

Brown’s campaign said that 71 percent of its donations came from Massachusetts donors, but it has also been subject to some criticism in the past for its own out-of-state support.

“If this were a situation where Scott Brown wasn’t getting any money from out of state this might be an issue,” former Boston City Councillor Lawrence S. DiCara ’71 said. He added that the dynamic of political fundraising has changed in recent years, with races increasingly drawing national support.

As Warren inches closer to Brown in the cash race, the actual race for votes appears to be even tighter. The most recent election poll, sponsored by The Boston Globe, showed Brown and Warren statistically tied.

—Staff writer Nicholas P. Fandos can be reached at nicholasfandos@college.harvard.edu.