WASHINGTON (CNN) -- Claiming "Mitt Romney's flip flops are enough to make John Kerry Blush," Kansas Sen. Sam Brownback's presidential campaign sharply criticized the Massachusetts Republican's record on abortion Monday evening.

The attack from Romney's camp is the latest sign the race for the White House has already reached a feverish pitch eleven months before the first wave of voters weigh in.

In a press release circulated Monday evening, Brownback's campaign claimed a Romney staffer falsely accused the Kansas Republican of once supporting abortion rights.

"This false allegation by the Romney campaign comes in light of recent evidence that Romney has switched positions on abortion at least three times," the press release said as it catalogued past statements Romney has made on both sides of the issue.

"It is absurd of Mitt Romney to compare himself to Sen. Brownback on the right to live issue," Brownback campaign manager Rob Wasinger said in the release.

Romney formally announced his candidacy Tuesday morning during a speech in Michigan. Brownback declared his White House bid late last month in his home state of Kansas.