(CNN) - It's back: President Barack Obama's birth certificate.
But instead of Donald Trump - a famous "birther" who posted online this week a video asking Obama to go public with his college records and passport - it was Obama himself raising the issue.
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"Once [Mitt Romney] took office he pushed through a tax cut that overwhelmingly benefited 278 of the wealthiest families in the state and then he raised taxes and fees on middle class families to the tune of 750 million dollars," Obama said at a Saturday rally in Nashua, New Hampshire, which borders Massachusetts, where Romney served as governor.
Among the increases, Obama said, were "higher fees to be a barber, higher fees to become a nurse. There were higher fees for gas, higher fees for milk."
"He raised fees to get a birth certificate," Obama continued, "which would have been expensive for me."
His audience laughing, Obama cracked a smile.
Behind the joke are the conspiracy theories of some conservative Republicans who maintain that Obama was not born in the United States, and is therefore not eligible to be president. Only "natural born" citizens of the United States are eligible to be president.
He released a certification of live birth during his 2008 presidential campaign, and in the spring of 2011, released his long-form birth certificate. Both show that he was born in a Hawaii hospital on August 4, 1961. Contemporaneously published newspaper announcements also noted the birth in the Aloha State.
Still, some - Trump among them - have questioned the authenticity of the documents.
The president last publicly quipped about his birth certificate in September when he met another native of Hawaii.
"You were born in Hawaii?" he asked Andre Wupperman, whose mother said he was born in Hawaii and would turn seven years old the next week. "Do you have a birth certificate?"
Romney campaign spokesman Ryan Williams responded to Obama's event, saying in a statement, "Today's desperate attacks are laughable coming from a President whose only plan for a second term is to recycle the failed policies of the last four years while raising taxes by $2 trillion. As governor, Mitt Romney worked with Democrats to close a $3 billion deficit, balance four budgets while cutting taxes 19 times, create tens of thousands of new jobs, and lower the Massachusetts unemployment rate to 4.7%."
New Hampshire is one of several battleground states which are seeing attention from both campaigns with the election just over a week away. The Granite State has four electoral votes.
– CNN's Ashley Killough contributed to this report