Des Moines, Iowa ? Two Republican presidential candidates are demanding apologies from fellow GOP hopeful Sam Brownback for questioning their opposition to abortion in automated phone calls to voters.

“Mitt Romney is telling Iowans he is firmly pro-life. Nothing could be further from the truth,” said the Brownback campaign’s phone message.

The message goes on to attack the former Massachusetts governor’s wife, warning: “His wife, Ann, has contributed money to Planned Parenthood.”

Romney spokesman Tim Albrecht expressed outrage at what he called “despicable, negative phone calls.”

“They should apologize to Ann Romney and Governor Romney for this personal attack,” Albrecht said.

Brownback’s campaign also has been making phone calls in Iowa that criticize Colorado Rep. Tom Tancredo for taking campaign money from a Planned Parenthood backer.

“Say no to Tom Tancredo and his Planned Parenthood friend, and help end abortion in America,” the caller says, according to a script confirmed by Brownback’s campaign.

Tancredo said Brownback, a Kansas senator, is a longtime friend who “is well aware of my lifelong commitment to the unborn.”

“I call on Senator Brownback to cease with the maliciously misleading push calls intended to harm me and apologize,” Tancredo said in a statement.

Brownback’s campaign stood by both calls.

“We stand by the accuracy of our statement that Mrs. Romney financially supported Planned Parenthood, the largest abortion provider in the world,” said spokesman John Rankin.

Rankin also said that Tancredo “says he is committed to being pro-life but has accepted thousands of dollars from the founder of a major Planned Parenthood network.”