Washington: Democratic presidential frontrunner Hillary Clinton on Friday apologised for praising former first lady Nancy Reagan's commitment to the fight against Aids in remarks which according to critics ignored President Ronald Reagan's dismissal of the AIDs for years.

"Because of both President and Mrs. Reagan, in particular Mrs. Reagan, we started a national conversation, when before nobody would talk about it. Nobody wanted to do anything about it," Clinton said on Friday, when she was in California to attend Nancy's funeral.

"And, you know," she added, "that, too, is something that I really appreciate with her very effective low-key advocacy, but it penetrated the public conscience and people began to say, hey, we have to do something about this too."

Clinton's remark raised a storm of criticism from those who are fighting Aids. They said that Ronald Reagan ignored growing concerns about the epidemic first diagnosed during his presidency in the 1980s.

Clinton later issued a correction on Twitter. "While the Reagans were strong advocates for stem cell research and finding a cure for Alzheimer's disease, I misspoke about their record on HIV and Aids," she wrote. "For that, I'm sorry."

"While I respect her advocacy on issues like stem cell and Parkinson's research, Nancy Reagan was, sadly, no hero in the fight against HIV/AIDS," tweeted Chad Griffin, president of the Human Rights Campaign, which advocates LGBT rights.