The Obama campaign says it received donations from more than 700,000 grassroots supporters during the 2012 convention week that ended Thursday – the latest announcement in an effort by both parties to raise enough cash for TV ads and other expenses through Election Day.

“We did it. Over 700,000 grassroots donations this week --thank you,” said a message Saturday from President Obama’s Twitter account.

The announcement was made just days after reports that the Romney campaign and the national Republican Party had raised at least $100 million in August, which would break that mark for the third straight month and bolster their cash advantage over the Obama campaign.

Obama and the Democratic Party have not released their August fundraising figures. Both campaigns' financial reports detailing sources of revenue and where the money is spent are due to the Federal Election Commission by Sept. 20.

Though the president and his party have outraised Romney and his party through the entire election cycle, they had less cash on hand as of July 31, and the gap is expected to widen during the final months.

In addition, Republicans and Romney have out-fundraised the president and his party for the past three months.

They raised a combined $101 million in July, $106 million in June and $76.8 million in May. The president and his party pulled in $75 million last month, and $71 million in June and $60 million in May.

Though Obama advisers say they enough money, they have some concerns about the amount of cash the campaign has been spending over the past few months on payroll, television ads and polling – all crucial to running a winning campaign.

In fact, Obama campaign manager Jim Messina made a plea from the stage at the party’s national convention earlier this week for more money.

"The other guys write $10 million checks and make $10,000 bets," he said. "But we've made this campaign bet on you."

In addition, Chicago Mayor and honorary Obama campaign Chairman Rahm Emanuel has left the campaign to help raise big-dollar contributions.

The Obama campaign has touts a strong ground game and so-called “campaign apparatus,” but such efforts are also expensive.  

Unless fundraising picks up, the campaign might be faced with such cost-reducing decisions as whether to cut salaries or scale back advertising or pull out of swing states, Democrats told The Wall Street Journal.

The Associated Press contributed to this report.