MOUNT AIRY, Maryland (CNN) -- U.S. President George W. Bush on Friday stressed the role of faith-based groups in the fight against AIDS, calling the struggle one of conscience and morals on the eve of World AIDS Day.

Activists call for more AIDS funding in front of the White House, draped with a giant red AIDS ribbon.

Bush was speaking at Calvary United Methodist Church in Maryland after meeting with representatives of religious and community groups.

"Faith-based groups like these are the foot soldiers in the armies of compassion," he said. "They are helping to defeat this epidemic one soul at a time."

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More than 2 million people have died of AIDS this year -- including 330,000 children.

Bush is asking Congress for an additional $15 billion to continue and expand the President's Emergency Plan for AIDS Relief, a program approved by Congress after he announced it in his 2003 State of the Union address.

On Friday, he announced plans to visit sub-Saharan Africa early next year to see the program at work. He renewed his call for lawmakers to continue funding it.

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"Now the time has come for the United States Congress to act again," he said. "I'm confident they will."

The White House says the program -- which targets countries hardest-hit by the disease -- has treated more than 1.3 million people with AIDS. Increased funding would boost that number to 2.5 million, while expanding AIDS prevention programs and offering care to millions more with AIDS.

Despite some successes, the program has been criticized for requiring that participating groups emphasize abstinence education.

At the White House, about 40 people carried signs in support of more AIDS funding.

Before speaking, the president, along with First lady Laura Bush, participated in an hourlong faith-based roundtable discussion at the church.

Among others, the president met with Martha Chilufya, founder of the Mututa Memorial Center in Zambia. The center works with faith-based and other caregivers to serve more than 150 patients.

Laura Bush and daughter Jenna visited the center in June. Bush said the first lady will join him on his trip next year.

A giant red ribbon -- the international symbol for AIDS awareness -- was hung from the north portico of the White House Friday morning "to represent the continued battle against HIV/AIDS and to affirm the matchless value of every life," the White House said. E-mail to a friend

CNN's Larry Lazo contributed to this report.

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