Reclusive chess legend Bobby Fischer has died at the age of 64 of an undisclosed illness, his spokesman has confirmed.

U.S.-born Fischer, who renounced his American citizenship and moved to Iceland in 2005, died Thursday at a hospital in Reykjavik, said spokesman Gardar Sverrisson.

At the age of 14, Fischer had already become a U.S. Open chess champion and by 15 he was the youngest international grandmaster.

In 1972, Fischer was propelled to international fame after his thrilling world championship win over the Soviet Union's Boris Spassky in Reykjavik.

The victory in the classic Cold War showdown made Fischer America's first world chess champion in more than a century.

However, Fischer quickly became known more for his idiosyncrasies than for his talent.

In 1975, Fischer forfeited his title to another Soviet, Anatoly Karpov, when he refused to play against him in Manila.

In 1992, after years in recluse, Fischer agreed to play Spassky again in an exhibition rematch on the Yugoslav resort island of Sveti Stefan.

Because of the location of the match, Fischer became a wanted man in the U.S. for violating sanctions imposed on the former Yugoslavia.

He then disappeared until after the 9/11 attacks. In an interview with a Phillippine radio station, Fischer applauded the strikes and said he wanted to see the U.S. "wiped out," reports Reuters.

Frank Brady, author of "Bobby Fisher: Profile of a Prodigy", told CTV Newsnet on Friday that the man's anti-Semitic remarks and anti-American statements helped to propel his infamy.

"Certainly he was the greatest chess player that every lived and he was famous because of what he did on the chess board, but he was certainly infamous for what he did off the chess board," Brady said.

Brady said Fisher's antics became increasingly more bizarre as he aged.

"He just sort of went bad, he went mean in the latter part of his life," he said.

However, Brady said the chess genius never uttered a controversial word prior to 1972, leading the first half of his life as a "polite" yet "arrogant" champion.

In July 2004, Fischer was held in a Japanese detention centre after having been caught trying to leave the country using an invalid U.S. passport.

Following his release in March 2005, Fischer unzipped his pants near the airport entrance and gestured as if he was going to urinate on the wall.

The outspoken Fischer accused Japan and the U.S. of "kidnapping" him.

Known for his anti-Semitic views, Fischer also said he was being hounded by the U.S because it was "Jew-controlled."

Reached in France, Spassky told The Associated Press he was "very sorry" to hear of Fischer's death.

With files from The Associated Press