Former Vice President Dick Cheney

Former Vice President Dick Cheney reluctantly commented today on the rift between his two daughters Liz and Mary Cheney, saying that he was surprised that Mary, who is lesbian, and her wife attacked Liz on Facebook.

"We were surprised that there was an attack launched against Liz on Facebook, and wished it hadn't happened," Cheney said at the National Press Club. "It's always been dealt with within the context of the family and frankly that's our preference."

After Liz Cheney, a candidate for Senate in Wyoming, made comments on Fox News Sunday indicating that she supports a "traditional" definition of marriage, her sister's wife Heather Poe took to Facebook to condemn the remarks.

READ: Dick Cheney Defends Daughter Liz in Gay Marriage Feud

"Liz has been a guest in our home, has spent time and shared holidays with our children, and when Mary and I got married in 2012 - she didn't hesitate to tell us how happy she was for us," Poe wrote on Facebook on Sunday. "To have her now say she doesn't support our right to marry is offensive to say the least."

Today, Cheney said the incident is "obviously a difficult thing for a family," but he declined to comment any further on the controversy or his position on gay marriage.

"That's as far as I'm going to go on the subject," Cheney told his interviewer. "Don't waste your time."

Cheney appeared with his doctor, Jonathan Reiner, to discuss their new book "Heart: An American Medical Odyssey," about his lifelong struggle with heart-related ailments.