Amy Chozick reports from Monroe, Mich., on the presidential race.

Barack Obama had harsh words for reporters asking about Republican vice presidential nominee Sarah Palin’s pregnant teenage daughter: Don’t go there.

“I think people’s families are off limits and I think people’s children are especially off limits. This shouldn’t be part of our politics. It has no relevance to Gov. Palin’s performance as a governor or her potential performance as a vice president and so I would strongly urge people to back off these kinds of stories,” Obama told reporters after a Labor Day BBQ in Monroe, Mich.

The response comes after Palin and her husband, Todd, released a statement that their 17-year-old unmarried daughter, Bristol, is five-months pregnant. A rumor circulating the blogosphere claims someone inside the Obama campaign leaked the pregnancy to the media. An unnamed McCain aide said the same to Reuters, according to the news wire service’s report.

Obama said he was “offended” by the accusation.

“We don’t go after people’s families, we don’t get them involved in the politics, it is not appropriate and it is not relevant. Our people were not involved in any way in this and they will not be. And if I ever thought it was somebody in the campaign that was involved in something like that they would be fired,” he said before getting into his campaign bus visibly disturbed by the question.

Obama had gathered reports to release a statement about Hurricane Gustav and the latest efforts to make sure evacuees have adequate facilities and can return safely to their homes as soon as possible. But the brief press conference quickly shifted to Palin’s daughter — the buzz of the day on both campaigns.

Obama and wife, Michelle, have tried to shield their two young daughters from the spotlight. The Democratic nominee came under criticism earlier in the campaign cycle for saying his wife, who actively campaigns on his behalf, was “off limits” to media scrutiny.