By Julien Pretot PARIS (Reuters) - Lance Armstrong returned four samples with traces of banned corticosteroids in the 1999 Tour de France, the International Cycling Union (UCI) said on Wednesday, although the governing body added it did not handle them as positive tests. On Tuesday the Belgian newspaper Het Nieuwsblad published a copy of an alleged internal UCI memo which said a lawyer for the sport's ruling body had said the American's samples from the 1999 showed traces of corticosteroids on four occasions.

Cycling's global governing body the UCI on Thursday announced that Russian rider Valery Kaykov had been suspended provisionally after failing an out-of-competition doping test. The UCI said that it acted after a lab in the German city of Cologne, accredited by the World Anti-Doping Agency, found that an A-sample of Kaykov's urine contained GW1516 sulfone. The substance was found in a test conducted on March 17 and is a so-called metabolic modulator -- which helps boost the production of hormones which can enhance an athlete's performance.

The rate of positive doping tests in South Korean sports reached a four-year low in 2012, the country's top anti-doping body said Tuesday.The Korea Anti-Doping Agency said it conducted 2,830 tests last year and 15 athletes tested positive for illegal substances.The KADA said it tested "B" samples for some athletes to confirm their doping. The positive test rate for 2012 came to 0.53 percent, the lowest since 0.49 percent in 2008.

World athletics championships hosts Russia on Monday rejected claims they are soft on doping, saying the exposure of a spate of high-profile cheats was due to a step forward in testing. A number of Russian athletes, including 2004 Olympic hammer champion Olga Kuzenkova, have been banned in recent months for doping violations, prompting calls in some quarters for Moscow to be stripped of its right to host the championships later this year.