London - Russian authorities are obstructing British anti-doping officials from testing Russian athletes, a British television channel said on Wednesday.
UK Anti-Doping (UKAD) was asked by the World Anti-Doping Agency (WADA) to oversee the testing of Russian athletes after the world body suspended Russia's Anti-Doping Agency (RUSADA).
Sky News, quoting unnamed anti-doping sources said, Russian authorities are impinging UKAD's ability to carry out testing.
Efforts have been frustrated by Russian officials asking for 30 days' notice of tests and disputing payments for doping control officers, the sources were quoted as saying.
Customs delays are also preventing the transport of blood samples to laboratories outside Russia within the 48-hour window needed for accurate testing.
As a result, the UKAD team are unable to match the 1 000 tests per month being carried out by RUSADA, Sky News added.
The Russian case is being discussed in Montreal this week by the WADA board which also suspended the Moscow anti-doping laboratory in April.
UKAD refused to comment on the Sky News report while WADA said it would do so only after its board meeting.
The news comes just a day after WADA said it was investigating fresh claims of Russian doping involving four unnamed Sochi 2014 Winter Olympic gold medallists.
The allegations - the latest in a slew of doping accusations to rock Russian sport - were made by whistleblower Vitaly Stepanov in an interview aired on Sunday by American channel CBS.
"The claims made in the programme offer real cause for concern, as they contain new allegations regarding attempts to subvert the anti-doping process at the Sochi Games," WADA president Craig Reedie said in a statement.
Russia's athletics federation is currently suspended by the International Association of Athletics Federations (IAAF) due to a large number of Russian doping failures and accusations of "state sponsored" doping.
Russia is battling to get its athletes reinstated in time for the Rio de Janeiro Olympics in August.
Contacted by Sky News about the obstruction claims, Russian Sports Minister Vitaly Mutko insisted the country has got its house in order.
"There is no basis for our team not to be participating in the Olympic Games. Athletics is hugely popular in Russia, most of our athletes are honest," said Mutko.
"We have been working with UKAD for four months. The first month it took 67 tests, the next month 150, now it is 200," the minister said.