Obama: 'I was black before the election'

Barack Obama mixed politics and humour and joked about racism issues surrounding his presidency as he made his debut appearance on a late-night US TV chat show.

No subject was out of bounds as the president joked with host David Letterman in what was a first appearance on the show by a sitting president.

Mr Obama even joked about how racism has entered the debate over his healthcare reforms.

"I think it's important to realise that I was actually black before the election," he said to laughter from the audience.

Letterman responded: "How long have you been a black man?"

His quip followed comments by former President Jimmy Carter that criticism of the president's healthcare plans was rooted in racism.

Mr Obama told Letterman he did not believe racism was involved, saying the very fact that he was elected "tells you a lot about where the country's at".

He continued: "One of the things that you sign up for in politics is that folks yell at you.

"Whenever a president tries to bring about significant changes, particularly during times of economic unease, there is a certain segment of the population that gets very riled up."

He cited the experiences of Franklin D Roosevelt, John F Kennedy and Ronald Reagan as examples.

The Letterman interview, which followed his appearance on five networks in one day at the weekend, marks the latest public relations effort from the president as he tries to win public support for his under-fire healthcare reforms.

While Mr Obama and Letterman shared good-natured banter there was a serious side to the 40-minute appearance with topics including Afghanistan and the economy being discussed.

He described the war in Afghanistan as a "real difficult situation" and said that he would be asking some hard questions before he committed any extra troops.

On a lighter note, Mr Obama said he worries about his daughters as they grow up to become teenagers in the White House. "I suppose they are going to want to go on dates," the president said, "and I'll have all these men with guns around. At that point they may have some stress."

He also joked that parents bringing their children to the White House to play with his daughters have to go through security and be frisked every time they arrive. And as is the custom with the Letterman show the host read out a top ten list - but this time it was reasons that the president had agreed to appear on the show.

They included "we told him Megan Fox would be here", and his supposed answer: "Said yes, without thinking, like Bush did with Iraq."