DES MOINES (AP) - Two Republican presidential candidates are demanding apologies from fellow GOP hopeful Sam Brownback.

They say he questions their opposition to abortion in automated phone calls to voters.

Brownback's campaign phone message accuses Mitt Romney of not being firmly pro-life. He also criticizes Tom Tancredo for taking campaign money from a Planned Parenthood backer.

Both candidates' campaigns are calling on Brownback to apologize for what they consider misleading messages.

Brownback spokesman John Rankin says the Kansas senator stands by the accuracy the claims.