In May 1983, in a paper published in the U.S. journal Science, a team from France's Pasteur Institute, led by Montagnier and including Barre-Sinoussi, described a suspect virus found in a patient who had died of AIDS.

Their groundbreaking discovery was also helped by U.S. researcher Robert Gallo's determination that the virus was indeed the cause of AIDS.

Both Montagnier and Gallo are co-credited with discovering that HIV causes AIDS, although for several years they staked rival claims that led to a legal and even diplomatic dispute between France and the United States.

Co-discoverer

The Nobel jury made no mention of Gallo in its citation. "We gave the prize for the discovery of the virus. The two to whom we gave the prize, Francoise Barre-Sinoussi and Luc Montagnier, discovered the virus," said Hans Joernvall of the Nobel committee.

Acknowledging that the American had "done a lot of other work" in the field, Joernvall noted that Gallo and the two French scientists now "agree that the discovery was made in Paris."

Robert Gallo congratulated the winners and said, "I am pleased my long-time friend and colleague Dr. Luc Montagnier, as well as his colleague Francoise Barre-Sinoussi, have received this honour."

He added: "I was gratified to read Dr. Montagnier's kind statement this morning expressing that I was equally deserving."

End to conspiracies

Another member of the jury, Bjoern Vennstroem, said he hoped the award would silence those who claim that HIV does not cause AIDS.

"We hope this will put an end to conspiracy theories and others who defend ideas that are not founded in research," he told Swedish Radio.

Montagnier, 76, is a professor emeritus and director of the World Foundation for AIDS Research and Prevention in Paris, while Barre-Sinoussi, 61, is a professor at the Pasteur Institute, also in the French capital.

"I must admit that I never for a moment dreamt I would hear such news," Barre-Sinoussi told French radio by telephone from Cambodia.