Democratic presidential candidate Sen. Barack Obama, D-Ill., climbs stairs to board a plane in Chicago

U.S. Democratic presidential candidate Barack Obama raised nearly twice as much campaign money as his Republican rival John McCain in July.

Senator Obama's campaign Saturday reported that it raised more than $51 million last month.

By contrast, Senator McCain's campaign raised $27 million in July.  McCain's campaign released its latest figure on Friday and noted the number had increased for a fifth consecutive month.

The rival candidates are expected to briefly share a stage Saturday during a forum on faith in the city of Lake Forest, in the west coast state of California.

The candidates are scheduled to give separate talks during the event hosted by the Reverend Rick Warren, author of the book titled "The Purpose-Driven Life"

The event marks Obama's return to the campaign trail after a week-long vacation in Hawaii.

Some information for this report provided by AP, AFP and Reuters.