Public health and AIDS experts hailed President Obama's announcement Friday to end a two-decade ban on people with HIV from entering the country, a restriction they described as archaic and discriminatory.

The United States is among just a handful of countries, including Yemen, Qatar and Sudan, that bar HIV-visitors from entering their borders.

The process to end the travel ban was started last year by Congress and the Bush administration. The president said his administration will finish it by publishing the final rules to eliminate the ban Monday. The ban is expected to be lifted early next year.

"It's just not supported by any evidence at this point - whether it was that people were coming into the United States and wildly infecting others or any other sound public health ground on which they could continue to exclude people," said Dana Van Gorder, executive director of Project Inform, an advocacy organization in San Francisco for people living with AIDS/HIV.

Obama made the announcement as he signed the fourth reauthorization of a federal program named for Ryan White, an Indiana boy who contracted AIDS through a blood transfusion. The program, started in 1990, provides funds for HIV-related care.

Attendees at the U.S. Conference on AIDS, which is being held this week in San Francisco, were elated by the news.

The ban was based on "old thinking about how you stop the progression of a disease without understanding the science," said conference attendee Ravinia Hayes-Cozier, director of government relations and public policy for National Minority AIDS Council. "The science and policy has finally caught up with each other."

In 1987, the U.S. health officials added HIV/AIDS to the list of communicable diseases that could prevent a person from entering the country. Congress, in 1993, codified the ban into law, which was signed by President Bill Clinton.

In 2006, the Bush administration said HIV-positive visitors could enter the United States on short-term or business visas without a special waiver. Then last year, President George W. Bush signed a law to repeal rules that prevented HIV-infected immigrants, students and tourists from receiving visas, without special permission, to enter the country. That step led to Friday's announcement to lift the entire ban.

Dr. Grant Colfax, director of HIV prevention and research for the San Francisco Department of Public Health, described the ban as discriminatory. He said the law was actually deleterious to public health.

"It encouraged people hiding and not getting tested," he said.

Health experts said visitors seeking permission to enter the country are asked about their HIV status, but it was difficult to determine how strictly the ban was enforced.

"Stigma and discrimination are huge (issues) for people living with HIV," said Lance Toma, executive director of Asian and Pacific Islander Wellness Center in San Francisco. "The travel ban is one that is in our laws that legalizes the stigma."