Hundreds of attempts to carry out drug tests on Russian athletes this year have been thwarted, the World Anti-Doping Agency (WADA) said Wednesday, in a bombshell report issued just days before a key decision on the country's participation at the Olympic Games. Drug testers had faced intimidation and threats from armed Russian security forces while athletes continued to evade doping control officers with a variety of techniques. The report comes just two days before the International Association of Athletics Federations (IAAF) meets in Vienna to decide whether Russian athletes should be allowed to participate in the Rio de Janeiro Olympics. But the explosive revelations in the WADA summary will raise fresh questions about Russia's repeated vows to clean up its drug-tainted sporting culture in time. The WADA summary said more than 736 tests between February 15 and May 29 were declined or cancelled for a variety of reasons ranging from sample collection or athlete whereabouts. Testers reported receiving hostile treatment when attempting to carry out drug tests in military cities, including intimidation and threats of expulsion from the country. Military cities are often given as a place of residence by athletes seeking to avoid drug testers because of the difficulty in gaining access to the areas, the report said. On other occasions, Russian coaches, doctors and venue staff had insisted on taking photographs of doping control officers' accreditation cards and paperwork. Other passages of the report highlighted the darkly comical lengths drug cheats would go to in an effort to avoid detection. One track and field athlete had been caught trying to provide a urine sample using a container inserted into her body. "When she tried to use the container it leaked onto the floor and not into the collection vessel," the report stated. The athlete subsequently threw away the container and then attempted to bribe the doping control officer. Other examples of obstruction occurred during an athletics event. One athlete was seen running away from a mixed zone in an effort to avoid being taken to doping control by a chaperone. Another athlete exited a stadium during a race and subsequently could not be found, the report said. At the Russian National Walking Championship on February 27, 15 athletes mysteriously did not start, withdrew or were disqualified, the report said.