Beijing's Winter Paralympics open Friday under the shadow of Moscow's invasion of Ukraine, with questions remaining over whether athletes from Russia and its ally Belarus will be barred from participating in the Games. As the first city to host both Summer and Winter Games, the National Stadium -- known as the Bird's Nest -- will once again light up for an opening ceremony to welcome hundreds of athletes from all over the world. Friday's celebrations could be muted, with the lead-up to the Games dogged by controversy as the world reacts with alarm to Russia invading Ukraine. That includes the International Olympic Committee (IOC), which on Monday urged sporting federations across the world to exclude athletes from Russia and Belarus, which had hosted troops before the invasion. But it remains up in the air if athletes from Russia -- who will compete for the Russian Paralympic Committee (RPC) following the country's ban for state-sponsored doping -- and Belarus will be barred from taking part in the Games. The International Paralympic Committee will have a meeting Wednesday and a decision is expected by the evening. Much of the sports world has reacted with solidarity to Ukraine.