Monte Carlo - China and the United States were among the most tested nations under the IAAF anti-doping programme in 2008, according to figures released by athletics' ruling body Thursday.

Russia, Belarus and Jamaica were also in the IAAF's top five countries for out-of competition testing last year but IAAF President Lamine Diack said attention had already shifted to nations participating in this summer's World Championships in Berlin.

"Our doping control programme for Berlin will the biggest yet put in place by the IAAF," he said. "We will have increased intelligent testing in the out-of-competition period leading up to the Championships, better testing during the Championships itself, and will store samples after the event for future analysis".

During the competition itself, the IAAF again plans over 1,000 blood and urine doping controls which is well in excess of the approximately 700 tests conducted on track and field competitors during the Beijing Olympic Games.

The IAAF will also begin implementing Biological Passports (both blood and urine) ahead of the worlds in August.

In 2008, the IAAF carried out a total of 3,4887 anti-doping tests, with over half (1,823) taking place out of competition. These figures do not include testing conducted by the International Olympic Committee at or before last summer's Beijing Olympic Games. (dpa)