GOP Sen. Scott Brown, who is locked in a fierce reelection fight in Massachusetts, suggested on Wednesday that he could be open to raising federal tax rates in the future.

“If you want to raise rates or do something as part of overall tax reform, I am all ears,’’ Brown told The Boston Globe in a story published on Thursday. 

A spokeswoman for Brown later told The Hill in an email that Brown was against raising taxes until Congress can show it is managing the money responsibly. 

The spokeswoman also said Brown was open to "raising revenues by closing loopholes" but did not mention the possibility of raising rates. 

"Scott Brown is opposed to raising taxes," spokeswoman Marcie Kinzel said in an email. "He knows that Washington is not a good steward of taxpayers dollars. Until Congress can show that it will manage taxpayers' hard-earned money responsibly, he believes we're better off stopping all tax increases and forcing Washington to do more with less."

"He is open to raising revenues by closing loopholes as part of comprehensive tax reform that lowers rates and doesn’t just grow government," she said.

Brown is among at least 40 Senate Republicans who have signed on to Grover Norquist's Taxpayer Protection Pledge, which is a commitment to oppose any net increase in federal taxes. Lawmakers could meet the pledge by agreeing to tax reforms that close some loopholes, but only if the result was a net reduction in tax revenue taken in by the government. 

In the same interview, Brown cast himself as the underdog to keep his seat against Elizabeth WarrenElizabeth Ann WarrenOn The Money: Trump 'ready' for tariffs on all 0B in Chinese goods | Trump digs in on Fed criticism | Lawmakers drop plans to challenge Trump ZTE deal On The Money: Trump rips Fed over rate hikes | Dems fume as consumer agency pick refuses to discuss border policy | Senate panel clears Trump IRS nominee Dems fume as Trump's consumer bureau pick refuses to discuss role in border policy MORE, the Democrat expected to face him next fall. Warren is a liberal favorite who was the architect of the Consumer Financial Protection Bureau included in the Wall Street reform legislation. 

Brown has cast himself as a centrist in the race against Warren, whom he called "very, very liberal" in the interview with the Globe. Brown criticized House Republicans last week for opposing a two-month extension of the payroll tax cut. 

Brown won his Senate seat in a special election in 2010, stunning the political world. The Senate seat, in deep-blue Massachusetts, had been held by the late Sen. Edward Kennedy. 

—This story was posted at 11:25 a.m. and updated at 3:58 p.m.