Republican US presidential challenger Mitt Romney raked in $106-million in June, sending incumbent Barack Obama a warning that he'll give him a run for his money in the November election.
Romney and the Republican National Committee now have $160-million in cash on hand, the campaign said on Monday, as the candidate gears up for a fierce four-month White House battle.
Four years ago the Obama camp bludgeoned rival John McCain with its own historic fundraising juggernaut, but last month its fundraisers fell $35-million behind its new Republican rival Romney.
The Democrat's campaign immediately placed Romney's impressive June tally at the heart of an opportunistic appeal to donors, telling them in an email that "we could lose if this continues".
June marked a second straight month of fundraising dominance for Romney.
"Last month, the GOP side out-raised and they called it a onetime fluke. Well, it happened again," RNC spokesperson Sean Spicer boasted in an email.
Romney's $106.1-million haul is a record for 2012 and well above the $71- million announced by Obama's re-election campaign, which was the president's best result of the year, topping the $60-million he raised in May.
"We still got beat. Handily. Romney and the RNC pulled in a whopping $106-million," Ann Marie Habershaw, chief operating officer for Obama's campaign, said in one of at least two emails soliciting new donations.
"This is no joke," she added. "If we can't keep the money race close, it becomes that much harder to win in November."
Habershaw noted the $106-million did not even include money to pro-Romney super PACs, the independent political action committees which raise unlimited funds to support candidates, although they cannot directly fund a campaign.
Obama also lags behind Romney when it comes to super PACs.
Wealthy conservatives are said to be funneling huge sums into outside groups that support Romney's agenda — including extended tax breaks, a rollback of industry regulations and full repeal of Obama health care reforms.
May was the first full month in which Romney emerged as the clear winner of a grueling Republican primary race, paving the way for him to step clear of party rivals and out-raise Democratic Obama for the first time.
Obama received donations from 706 000 individuals in June, including 181 000 who gave for the first time, while Romney received funds from about 570 000.
June's figures were significant for Romney in part because they showed a dramatic increase in grass-roots donations, turf Obama has broadly dominated.
Romney received more than 536 000 donations of less than $250 last month, compared to 297 000 donations under $250 in May.
Romney, who holds a campaign rally Tuesday in Colorado, is reportedly holding fundraisers in the wealthy resort town of Aspen on Monday night.
Obama is hitting the money trail the same night, attending a pair of closed-door events in Washington.
Despite the fundraising advantage, Romney's team has insisted it is Obama who is currently spending more on getting out his message.
In a memo dated Sunday, the Romney campaign said it has been outspent $46.2-million to $17-million on advertising since Romney won the Republican primary race in April.
That figure does not include super PAC money spent on advertising.
Pro-Romney group Crossroads GPS said on Friday it purchased a $25-million ad blitz in nine battleground states to attack Obama's record on jobs and the national debt.