some have also been discovered among athletes and staff living in what's known as the closed loop system. it's a quarantine bubble cut off from the rest of the city. cnn's steven jiang live in beijing. what happens when a positive case is found in the closed loop? >> reporter: well, then they have to be isolated. as you say, this covid containment policy continues to be the top priority for the organizers and authorities, both in and out of the loop. out of loop actually not far away from the bird's nest, that's a stadium where the opening ceremony will be held in a few days. authorities have sealed off a few apartment blocks because of some fresh cases there, but inside the loop, as you said, which is completely sealed off from the rest of the city, more cases on monday. 24 people tested positive. some of the athletes actually testing positive are speaking out, including american bobsledder alana myers tater. she is a three-time olympic medalist. this is her fourth games.