Washington (CNN) -

The Obama re-election team raised more money last month than any campaign has brought in this election cycle, a Democratic source familiar with the fundraising totals confirmed to CNN.

The campaign's September total is expected to exceed $150 million, the source said.

That would top the previous monthly record of $114 million for Obama, set in August.

Officials refused to comment on campaign fundraising numbers as the donations are still being counted.

The fundraising information was first reported by the Wall Street Journal earlier Thursday.

Making sure each campaign has plenty of cash is key as the critical final weeks of the campaign approach - especially with a vigorous and now escalating TV ad battle ongoing in at least eight swing states.

September started with the Democratic National Convention and a well-received speech by former president Bill Clinton resulting in a bounce in the president's poll numbers. That helped solidify support for the re-election effort.

Obama is jointly raising money with the Democratic National Committee just as Mitt Romney is doing so with the Republican National Committee.

For Obama, August reversed a trend of several months in which Republicans out-raised the Democrats on the presidential front.

Romney brought in $112 million in August.

For the first time in history neither major presidential nominee is accepting federal matching funds in the general election campaign, only intensifying the chase for dollars.

One advantage for the president has been his ability to attract more small donors who can repeatedly give while the Romney campaign has drawn more large dollar contributors. Obama's campaign earlier this week announced it raised money from more than 10 million individual donors.

Romney officials have not yet indicated what their September fund-raising totals. Both campaigns have until October 20 to report their tallies to the Federal Election Commission.