VIENNA, Austria — Rights groups have called on the United States to lift travel restrictions on sex workers and drug users — who were featured significantly in this year's International AIDS Conference that ran from July 18 - 23 in Vienna — as Washington gets ready to host the next International AIDS Conference in 2012.

The calls came even as the US reiterated its commitment to redouble its efforts to prevent and treat HIV/AIDS in that country and worldwide.

"For 2012 to be effective we must ensure individuals from key affected areas be granted the right to enter the US," said Patricia Perez, chair of the International Steering Committee of the International Community of Women Living with HIV/AIDS.

She expressed concerns that sex workers, drug users and persons with criminal records will be denied entry.

"It is therefore imperative that the International Aids Society (organisers of the conference) work with the US to ensure people are not denied their rights to participate because of visa issues," she told delegates attending the closing ceremony of the XV111 AIDS Conference on Friday.

Scores of delegates, among them media workers from developing countries, were denied Schengen visas to enter Austria, stirring fear among participants that the situation could get worse in the United States where it is harder to qualify for a visa.

But President Barack Obama, in a video message to delegates, said his country looked forward to hosting the conference.

"I look forward to welcoming all of you to Washington DC in July 2012," he said.

Obama also reiterated the US' commitment to fighting the worldwide pandemic, pointing out that his administration had redoubled efforts to prevent and treat HIV/AIDS both in that country and around the world.

"That's why, even in a tough fiscal environment, I have asked for increases to the Presidents' Emergency Plan For AIDS Relief (PEPFAR) in both my budgets, 2011 being the largest PEPFAR budget to date," he said.

Obama announced also that the US had embedded PEPFAR in a comprehensive Global Health Initiative to help other countries improve health care, save lives and increase life expectancy.

Pointing to what he said were clear goals to accomplish this, Obama said "we are going to double the number of babies born HIV-free and work to prevent more than 12 million new infections."

"We will provide direct support to more than 4 million people on treatment and we will help more than 12 million people including 5 million children and orphans get the care they need," he added.

Meanwhile, The US president said he was committed to also ending the HIV epidemic in his country, which records 56,000 new cases each year -- with the majority concentrated in a few communities, including gay and bisexual men, African Americans, Latinos and substance abusers.

"That is why my administration released a National HIV/AIDS Strategy that increases our focus on reducing the number of new infections in these high-risk groups and making our entire nation healthier," Obama said.

The strategy, he explained, will also involve increasing access to care, reducing HIV-related health disparities and improving co-ordination across the government and private sector.

In the meantime, Secretary of State Hilary Rodham Clinton, speaking also via video link, said the United States -- working through PEPFAR and the Global Fund -- is the largest contributor to global AIDS programmes.

"We are focused on reducing the impact on families and communities when the virus claims women of reproductive age, passes from mother to child or is spread through gender-based violence," she said..

"We believe access to HIV/AIDS prevention, treatment, and care should be a universal, shared responsibility, because health is a human right," she added.

An estimated 33 million people worldwide are said to be infected with HIV. Some 32,000 persons are believed to be infected in Jamaica, 50 per cent of whom do not know their status.