Estonia has become the latest country to say it will not allow Russian or Belarusian athletes to compete on its territory as a result of the ongoing war in Ukraine.
It comes after Norway, Finland and Canada made similar announcements.
The moves come amid a mounting backlash over the reinstatement of athletes from Russia and Belarus.
In September, the International Ski Federation (FIS) relaxed its rules, saying competitors from the two countries would be granted access to its events "provided that they sign a declaration of neutrality".
They had previously faced more stringent background checks on any voluntary link or paid duty with the military.
Participation remains limited to individual events, with athletes banned from displaying national symbols such as flags, anthems or uniforms.
However, it has now emerged that Estonia's government has written to the FIS, claiming that allowing entry to competitors from Russia and Belarus would undermine the country's support of Ukraine, and present an opportunity for propaganda.
In a statement issued to BBC Sport, the FIS said it "is committed to offering full support to athletes, national ski associations and local organisers - with most of which we have a long-standing relationship - in the process of navigating what we know to be a very complex situation.
"With that said, the Individual Neutral Athlete policy is clear in stating that notwithstanding eligibility, the host country visa and entry policies remain in place and are determined solely by the host country. FIS bears no responsibility for denial of visas or entry to any person granted eligibility under the FIS Individual Neutral Athlete Policy."
On Thursday, Scandinavian neighbours Norway and Finland both said they would also block visas for Russian athletes because of the war in Ukraine.
Norway is preparing to host the cross-country skiing World Cup next month, while Finland is due to stage the figure skating world championships in March. The International Skating Union (ISU) has said it "believes that athletes should not be punished for the actions of their governments in a world where, sadly, many conflicts are ongoing", and that it was "seeking clarifications" from officials in Finland.
This comes in the wake of last month's decision by the Court of Arbitration for Sport (Cas) to overturn a ban of Russia by the International Ice Hockey Federation (IIHF), a move condemned by the British, German, Finnish and Czech federations.
Russia have been suspended from competing in IIHF events since the country invaded Ukraine in February 2022, but the Russian Ice Hockey Federation (RIHF) then successfully appealed that decision at Cas.
The Canadian government has informed its hockey authorities that it will not issue visas for Russians to play in next month's World Junior Championship, including those who currently play for teams in Canada, as long as the war continues. A number of countries had said they would refuse to play against Russia, if they were allowed to take part.
Despite the controversy, the return of Russia and Belarus to international sport has been gathering pace this year.
In March, several athletes from the two countries were allowed to compete under their national flags at the Winter Paralympics after partial suspensions by the International Paralympic Committee were lifted.
In July, the International Olympic Committee (IOC) provisionally reinstated Russia to its competitions, stating a ban introduced in 2023 after the invasion of Ukraine was "no longer applicable".
However, sports federations can still enforce their own eligibility criteria. While World Gymnastics, World Aquatics and World Boxing have all removed restrictions on Russian athletes competing, a total ban has been maintained by World Athletics.
