It's all-out war between David Letterman and Sarah Palin over a shocking joke the late night host made about the former vice presidential candidate's daughter.

An enraged Palin fired off a statement saying:

"Laughter incited by sexually perverted comments made by a 62-year-male celebrity aimed at a 14-year-old girl is...disgusting..."

The joke that lit the fuse came during Letterman's monologue on Wednesday evening. "One awkward moment for Sarah Palin at the Yankee game...during the seventh inning, her daughter was knocked up by Alex Rodriguez."

Letterman explained that the joke was about Palin's 18-year-old daughter Bristol, not 14-year-old Willow, who was at the game with her mom.

"I would never, never think it was funny to use a 14-year-old girl as a joke for God's sake," countered Letterman.

Letterman extended an olive branch to the Palins, inviting them to be guests on his show, but the onetime vice presidential hopeful wasn't interested. A Palin spokesman said:

"The Palins have no intention of providing a ratings boost for David Letterman by appearing on his show. Plus, it would be wise to keep Willow away from David Letterman."

Ouch! The matter even reached political levels, as Senator Claire McCaskill, a Democrat from Missouri, weighed in on her Twitter page:

"Letterman jokes about Palin's daughter. Way over the line. If it were my daughters I'd be furious. He should seriously apologize."

Letterman did apologize, but in his own inimitable way.

"Were the jokes in questionable taste? Of course they were. Do I regret having told them? Well, I think probably I do. But you know what? There are thousands of jokes I regret telling on this program."