Russian Vladimir Arnold, one of the most important mathematicians of the 20th century, died Thursday in France just a few days short of his 73rd birthday, Russian news agencies reported.

Arnold, who arrived in France about two months ago for medical treatment, was suddenly taken ill with peritonitis and admitted to a Paris hospital on Wednesday, reports said citing his associates.

"It happened very suddenly. He was admitted to hospital yesterday (Wednesday) evening. He underwent surgical intervention but he did not survive the operation," said Maxim Kontsevich, a mathematician friend living in France.

Born on June 12, 1937 at the Ukraine port city of Odessa, Arnold was notably the coauthor of the KAM theorum of classical mechanics developed in the 1950s and bearing the initials of its creators, Kolmogorov, Arnold and Moser.

He "was one of the most eminent contemporary mathematicians from all points of view," said the Russian Academy of Sciences vice president Valeri Kozlov, cited by the Itar-Tass agency.

"His work contained many things indispensable to the other sciences," including physics, chemistry and biology, Kozlov said.

In 1974 the Soviet Union opposed Arnold's award of the Fields Medal, the most prestigious recognition in work in mathematics that is often compared to the Nobel Prize, making him one of the most preeminent mathematicians to never receive the prize.

Arnold however received many other awards for his work, including the Crafoord Prize in 1982 and the World Prize in Mathematics in 2001.

He became a member of the French Academy of Sciences in the 1980s.

Arnold worked at the Steklov Mathematical Institute in Moscow and then the Moscow State University before he retired.