Evan Vucci, File, Associated Press
FILE -In this June 8, 2012 file photo, Republican presidential candidate, former Massachusetts Gov. Mitt Romney talks with his staff while riding on his bus after a campaign stop in Council Bluffs, Iowa. Keeping his secrets, Romney tends to lift the veil on his finances and campaign only if the law says he must. The Republican presidential candidate refuses to identify his biggest donors who "bundle" money for his campaign. He often declines to say who meets with him. He puts limits on media access to his fundraisers. And he resists releasing all of his tax returns, making just a single year public after facing pressure to do so. He says he gives out all the information that's required by law.

WASHINGTON (AP) — Republican presidential candidate Mitt Romney said in an interview to be published Sunday that one reason he's reluctant to release his tax returns is that they reveal how much money he and his wife have given to the Mormon church.

In an interview with Parade Magazine, Romney said his church "doesn't publish how much people have given."

"This is done entirely privately," Romney told Parade. "One of the downsides of releasing one's financial information is that this is now all public, but we had never intended to our contributions to be known."

Romney said his contributions to his church are "a very personal thing between ourselves and our commitment to our God and to our church."

Democrats have hammered Romney for refusing to release any tax returns beyond his release of his 2010 return and a summary of last year's tax information. He has said he plans to release his full 2011 return before the Nov. 6 election.

Romney hasn't previously mentioned his reluctance to reveal charitable donations as a rationale for keeping his taxes private.

Ann Romney, who joined her husband for the interview, said she loved tithing and that it makes her emotional.

"When Mitt and I give that check," she said, "I actually cry."