New York City ? Sen. Joe Biden spent his first day as an official presidential candidate regretting a gaffe that could spell trouble for his newborn campaign.

The six-term Delaware lawmaker, who has said for months he’d be a candidate in 2008, formally establish his presidential committee Wednesday and launched a campaign Web site. It’s the second presidential bid for Biden, who pursued the White House in 1988.

In an interview with the New York Observer, Biden called another leading Democratic candidate, Sen. Barack Obama, “the first mainstream African-American who is articulate and bright and clean and a nice-looking guy.”

Biden was peppered with questions from reporters in an afternoon conference call, and late in the day, issued a terse statement, saying: “I deeply regret any offense my remark in the New York Observer might have caused anyone. That was not my intent and I expressed that to Senator Obama.”

Biden told reporters that he’d used the word “clean” to describe Obama as “fresh and new,” and that the choice of words was not meant to disparage other black candidates who’d run for president in the past, such as civil rights leaders Jesse Jackson and Al Sharpton.