The International AIDS Conference opened Sunday with a call for the world's governments not to let tight budgets slow the fight against the disease.

San Francisco AIDS specialist Dr. Diane Havlir told delegates to the conference in Washington, D.C. that the world has a chance to “start to end AIDS.” She said it would be an extraordinary failure of global will and conscience if financial cutbacks blocked that chance.

The United Nations says 34 million people lived with HIV / AIDS and 1.7 million died from the disease in 2011.

This year's conference, called “Turning the Tide Together,” is expected to attract more than 20,000 people. High-profile guests include former U.S. President Bill Clinton, former first lady Laura Bush, singer Elton John and actress Whoopi Goldberg.

More than 1,000 people marched through downtown Washington on Sunday to call attention to HIV / AIDS.

The biennial conference is being held in the United States for the first time in 22 years, after President Barack Obama lifted the U.S. ban on HIV infected travelers entering the United States.