Former world chess champion Bobby Fischer died of an unspecified illness, a spokesman for the late champion said on Friday. He was 64.

Fischer, who beat Russian Boris Spassky in 1972 to become world champion, was considered by some chess experts to be the greatest player of all time.

A spokesman for Fischer confirmed the death in a statement sent to Reuters by e-mail. The American-born Fischer had settled in Iceland in 2005 and was later granted Icelandic citizenship.

• Bobby Fischer fact file

Born in March, 1943, Fischer was America's first and only world chess champion, winning the title in the classic Cold War showdown in Reykjavik in 1972.

Failing to defend his crown in Manila in 1975, world chess authorities awarded it to his challenger, Anatoly Karpov.

He was US junior champion at 13 and U.S. Open champion at 14, and the youngest international grandmaster ever at 15.

Fischer fell foul of US authorities by playing a match against Spassky in Yugoslavia in 1992, at a time when the country was the target of sanctions during Belgrade's war with breakaway republics.

He vanished after the match, for which he won $3 million, and resurfaced only after the Sept. 11, 2001, attacks in the United States. In an interview with a Philippine radio station, Fischer praised the strikes and said he wanted to see America "wiped out".

Fischer was granted Icelandic citizenship in March 2005 after eight months in detention in Japan [Images] fighting a U.S. deportation order.