US former President Bill Clinton vowed yesterday to help Barack Obama, who beat his wife, Hillary, in the Democratic presidential nomination race, to win the bid for the White House.

"(Former) President Clinton is obviously committed to doing whatever he can and is asked to do to ensure (Illinois) Senator Obama is the next president of the United States," said Matt McKenna, Clinton's spokesman.

It was the first time for the two-term president from 1993 to 2001 to make public comments in support Obama since his wife suspended the campaign on June 7.

However, the spokesman did not elaborate on what the former president would do to help Obama's campaign.

In return, Obama's campaign spokesman Bill Burton said that they were confident in former President Clinton to "play a big role" in building a unified Democratic Party "to be a powerful force for change this year."

The former First Lady and New York Senator, Clinton, who also promised to do what she could to help Obama to be the first African-American president in the country, is expected to join Obama in a private fundraising event on Thursday and a public campaign rally on Friday.