U.S. President Barack Obama and Republican challenger Mitt Romney poked gentle but sharp fun at one another Thursday night during an esteemed New York Catholic charity dinner that has long been a required stop for presidential candidates.

Romney mocked his own wealth while taking aim at the president for running up the federal debt while Obama noted the "nice long nap" he had taken during the first presidential debate.

The two rivals donned tuxedos and white ties to share the dais at the Alfred E. Smith Memorial Foundation Dinner, an annual gala that has drawn political leaders and other notables since the end of the Second World War.

The event was a comedic pause in a contest that has drawn increasingly nasty and close with less than three weeks left before the Nov. 6 election. On Tuesday, Obama and Romney sparred in a nationally televised debate in which each questioned the other's character and truthfulness.

'So little time, so much to redistribute'

Romney spoke first at the dinner, which was set to raise $5 million for Catholic charities. Addressing the elegantly dressed crowd, Romney, a millionaire many times over, said "it's nice to finally relax and wear what Ann and I wear around the house." Of Obama, Romney said: "You have to wonder what he's thinking. So little time, so much to redistribute."

Obama followed, noting his soporific performance in the first debate but also chiding Romney for his wealth.

"Earlier today I went shopping at some stores in Midtown," Obama said. "I understand Gov. Romney went shopping for some stores in Midtown."

Obama noted that he was preparing for the final debate with Romney on Monday, which will focus on foreign policy.

"Spoiler alert: We got bin Laden," Obama said, referring to the military mission that killed the mastermind of the Sept. 11, 2001, terror attacks.

Jon Stewart questions Obama on Libya

In a television interview earlier Thursday, Obama rejected criticism that his administration has offered a confused response to the attack on the U.S. Consulate in Libya, an accusation Romney has made repeatedly in the campaign for the White House. Of any breakdown that might have led to the killing of four Americans, Obama declared, "We're going to fix it."

Obama made the comments on The Daily Show on Comedy Central. Host Jon Stewart turned serious in pressing Obama over the government's changing explanation about the attacks in Benghazi. When Stewart suggested that even Obama would concede his administration's coordination and communication had not been "optimal," Obama said: "If four Americans get killed, it's not optimal. We're going to fix it. All of it."

U.S. President Barack Obama participates in a taping of the Daily Show with Jon Stewart at the Comedy Central Studios in New York. Stewart pressed Obama on the president's response to the recent attack on the embassy in Libya. (Jason Reed/Reuters)

Romney has pointedly questioned Obama's handling of the matter and his honesty about it to Americans. Those accusations led to the fiercest conflict of the presidential debate on Tuesday and will surely come to the fore again on Monday in the campaign's final debate.

Obama insisted information was shared with the American people as it came in. The attack is under investigation, Obama said, and "the picture eventually gets filled in."

The exchange came on a day when Vice President Joe Biden compared the policies of Romney's running mate, Rep. Paul Ryan of Wisconsin, to a gun pointed at Americans, and after Romney's son said he was tempted to "take a swing" at Obama when the Democrat questions the GOP candidate's honesty.

Ryan, speaking at a campaign stop in Ocala, Fla., before Biden made his comments in Nevada, accused Obama of sending a divisive message.

"He's basically trying to disqualify his opponent with a sea of negativity," Ryan said. "He's trying to divide this country, pitting people against each other. He's trying to win this election by default. You know what? We're not going to let him get away with that."

Battle heats up

The sharpness of the barbs is a reflection of just how tight the race is 19 days out. Hard campaign decisions are being made, state by state.

Romney aides said Thursday that no staff had been dispatched to Michigan or Pennsylvania, where they once suggested he would compete aggressively but has not.

The bickering between campaigns eased briefly at the Smith dinner, named for the four-term Democratic governor of New York who lost the 1928 presidential race to Republican Herbert Hoover. Smith was the first Catholic to run for president and the dinner named for him is organized by the Catholic Archdiocese of New York for the benefit of needy children.

Democrats are pushing the accusation that Romney is being dishonest, taking up Obama's refrain since Tuesday's debate that the Republican nominee is offering "a sketchy deal."

'I wasn't confused about the fact that we're going to hunt down whoever did it and bring them to justice,'—Barack Obama on Libya

"I don't think they were just sketchy," Biden said at a rally in Las Vegas. "I think they were Etch-a-Sketchy."

Obama and Biden are to campaign together next Tuesday in Ohio after Monday night's debate.

On Libya, Obama has faced scrutiny for shifting explanations of what happened. He pushed back on The Daily Show.

"We weren't confused about the fact that four Americans had been killed," Obama said.

"I wasn't confused about the fact that we needed to ramp up diplomatic security. ... I wasn't confused about the fact that we had to investigate exactly happened so it gets fixed. And I wasn't confused about the fact that we're going to hunt down whoever did it and bring them to justice," the president said.

On another national security issue, Obama said he still wants to close the prison for terrorism suspects at Guantanamo Bay, Cuba, a big unmet promise of his 2008 campaign. The effort was blocked by Congress, which passed a law prohibiting the government from moving prisoners to the U.S. for detention or trial.

On the celebrity front, Obama picked up the endorsement of rock star Bruce Springsteen, who also backed the Democrat in 2008 and Thursday campaigned for him in Ohio with former President Bill Clinton.

"For 30 years I've been writing about the distance between the American dream and American reality," Springsteen said, reading from a statement on his music stand. "Our vote is the one principal way we get to determine that distance."