Senator Barack Obama waves to tourists from Illinois as he is followed by the news media through the U.S. Capitol, Thursday, 08 May 2008 in Washington

U.S. Democratic presidential hopeful Barack Obama has picked up the support of two more superdelegates in the battle for the party nomination.

His campaign announced Friday that congressmen Peter DeFazio and Don Payne are endorsing the Illinois senator. Payne previously backed Obama's Democratic rival, Senator Hillary Clinton.

Obama visited the U.S. House of Representatives Thursday to seek the support of superdelegates, who are elected officials and party activists who are free to support either candidate at the party convention in August. They may be the deciding factor in who wins the nomination.

In West Virginia Thursday, Clinton urged her supporters to ignore political observers who have declared her candidacy finished. She is favored in the West Virginia primary next week.

Two-thousand-twenty-five delegates are needed to secure the Democratic Party presidential nomination. Obama leads Clinton, and is less than 200 delegates away from that figure.

On Tuesday, Obama scored a 14-point victory over Clinton in the North Carolina primary, while Clinton edged out Obama in Indiana.

Other superdelegates to recently announce their support for Obama include former congressman David Bonior of Michigan and former senator and 1972 presidential candidate George McGovern, who switched his support from Clinton to Obama.