President-elect Barack Obama appeared Thursday at Democratic Party headquarters with his hand-picked incoming chairman, Virginia Gov. Tim Kaine.

But his predecessor, outgoing chief Howard Dean, was nowhere in sight.

Dean, who has clashed with Obama's top aides and Democratic leaders in Congress during his four-year term, is stepping down January 21.

Obama spokesman Tommy Vietor says Dean couldn't attend because he was traveling.

Obama's transition officials, however, did not immediately respond when asked whether the former Vermont governor was invited to appear at the news conference.

But Democrats with knowledge of the situation, who spoke on the condition of anonymity to avoid angering the Obama team, say Dean didn't attend the event at the request of Obama advisers.

Thought Kaine plans to work at the party part time until 2010, Virginia Republicans have criticized Kaine for taking the political job while serving as governor.