Speaking to Russia's state news agency TASS, coach Sergei Turyshev, who works with Kramer and the same group, explained the difficulties the German coach was facing.

Russia's international borders have been largely closed in an attempt to curb the spread of the deadly virus.

Kramer's coaching group features two-time world champion Sergei Ustyugov, Olympic cross-country medallist Yulia Stupak, and World Championship medallist Gleb Retivykh.

Other athletes include Evgeny Belov, Ivan Kirillov, Artem Maltsev, Alisa Zhambalova and Maya Yakunina.

The group's first two summer training camps were not attended by Kramer due to the COVID-19 pandemic preventing him from entering Russia, and he still has not been able to link up with the team.

"Markus currently continues to be at home, he is still deprived of the opportunity to join us at the training camp due to the fact that he cannot get a visa to enter Russia due to the pandemic," Turyshev said.

"He has already discussed this problem with the Minister of Sports and he promised all kinds of assistance.

"As soon as the visa is in hand, Kramer will immediately come to Russia.

"He is constantly in touch with us - as for the training camp itself, everything is going according to plan.

"If any questions arise, we immediately resolve them - the training process is underway, the athletes are preparing for the season, everything is fine."

The camp is set to run from August 9 to 29.