HELENA — Incumbent GOP Sen. Conrad Burns is closing in on $7 million raised for his re-election effort, an amount the campaign says is a record for a U.S. Senate campaign in Montana.

The campaign released its finance reports Friday, showing it had raised about $870,000 for the quarter ending June 30, more than $6.8 million so far and had about $2.2 million on hand.

Democratic challenger Jon Tester’s campaign said fundraising totals would not be available until today.

The Burns campaign also said its campaign finance report would show that it is paying for a lawyer who has been reviewing complaints related to donations linked to lobbyist Jack Abramoff out of the campaign account.

The campaign said that the Senate Ethics Committee had approved the use of campaign funds to pay for the law firm of Powell Goldstein, which specializes in congressional investigations.

The law firm has been paid about $64,000 so far, said Burns campaign spokesman Jason Klindt.

‘‘Powell Goldstein was retained to complete a thorough review of the facts relating to matters that have been the subject of political attacks on Senator Burns. They are also advising the campaign on routine (Federal Elections Commission) compliance guidelines,’’ he said.

Democrats have played up Burns links to Abramoff, who pleaded guilty as part of a federal corruption investigation earlier this year. The barrage of attacks have made Burns vulnerable, and Democrats are hoping Tester can take advantage in what is shaping up to be a close race.

The Burns campaign said its fundraising total surpassed the $6.2 million Sen. Max Baucus, D-Mont., raised in his 2002 re-election effort.

The Burns campaign has been using a strategy of labeling Tester as a liberal who only looks like a rural Montanan, and took advantage of the campaign release to make another jab.

‘‘We know that every extremist left wing group in the country is going to donate to liberal Jon Tester,’’ Klindt said. ‘‘We have an obligation to defend ourselves from those attacks and we will be ready.’’

GOP incumbent U.S. Rep. Denny Rehberg reported raising about $238,000 during the second quarter, a total of $787,000 since the campaign started and had $652,975 on hand.

‘‘This fundraising report is just one more example of the tremendous support were seeing,’’ Rehberg said in a release.

Democratic House challenger Monica Lindeen reported raising about $106,000, a total of roughly $363,000 since she entered the raise and said the campaign had about $183,000 on hand.