The fund-raising machine behind Mitt Romney and the Republican Party once again bested President Obama’s effort last month, raising $25 million more in July than the president and his Democratic allies did.

Mr. Romney and the Republican National Committee raised $101.3 million in July, his campaign announced Monday, as Republican donors rallied behind their presumptive nominee with the national convention only a few weeks away.

The president’s campaign announced on Twitter on Monday morning that his July fund-raising topped out at about $75 million. “Every bit helps,” the campaign tweeted, noting that 98 percent of the contributions were under $250.

Mr. Obama’s advisers have all but conceded the money race to Mr. Romney. Fund-raising e-mails from the campaign have taken a more urgent tone over the summer, repeatedly warning supporters of the financial advantage that the Republicans will hold going into the final weeks of the presidential campaign.

More detailed information about the July fund-raising has not yet been released by the two candidates. All campaigns are required to report their fund-raising to the Federal Election Commission by Aug. 20.

But the Republican figure keeps Mr. Romney and his party on pace to bring in $800 million for the cycle, the target set by Mr. Romney’s team in April. Roughly a quarter of the Republicans’ haul, $25.7 million, came in donations of under $250, as Mr. Romney worked to increase his appeal among small donors.

The campaign, the Republican National Committee, and a joint fund established by the Republicans to raise presidential campaign cash ended July with $185.9 million in cash on hand. They did not disclose what proportion of the money would end up in Mr. Romney’s campaign coffers, which can only accept $5,000 from each donor every election cycle, and how much to the R.N.C., which can accept 10 times that amount from each donor.

The strong fund-raising puts renewed pressure on President Obama to bring in more cash and underscores the near-certainty that Mr. Romney will remain financially competitive with an incumbent whose fund-raising prowess has long been a hallmark.

While Mr. Obama steadily raised more than Mr. Romney in 2011 and early this year, he has also spent far more, amassing a campaign tab of more than $400 million with the Democratic National Committee through the end of June.