(Reuters) - North Korea’s Pyongyang marathon may be among the most complicated to enter but an easing of tensions on the Korean peninsula has made it a stage to highlight the power of sport amid growing interest for the race.

Athletes can only register through one operator, Koryo Tours, for a chance to run through the capital of the reclusive state in the Mangyongdae Prize International Marathon, as the race is officially known.

But close to 1,000 foreigners -- several hundred more than last year -- signed up in the sixth year foreign runners are allowed to compete on Sunday, according to officials, as tensions between North Korea and South Korea have eased since 2018.

Among those running were two Olympians -- retired Swiss freestyle skier Mirjam Jaeger and British snowboarder Aimee Fuller -- who are part of a documentary produced by the Olympic Channel on the Pyongyang marathon and the pair’s experience of the local sports culture.

The Olympic Channel is a media operation of the International Olympic Committee and the documentary is set to air in September.

“The start (in Kim Il Sung Stadium) was very busy, the stadium completely full,” Fuller, who took part in the 2014 and 2018 winter Olympics, told Reuters in a telephone interview from the North Korean capital.

“It felt as if we were on a world stage competition. That was completely surreal. It was like the Olympics in an Olympic stadium.”

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Large crowds also lined the street at the start of this world athletics body IAAF-accredited bronze label road race with women wearing traditional costumes ready at refreshment stations.

“Around mile 13 it definitely started to thin out. Having that unique opportunity to move from Pyongyang out into the countryside was really surreal.”

Politics, however, is never too far away from the Pyongyang marathon, with visitors promised a tour of the capital’s landmarks “including a visit to the famous Victorious Fatherland Liberation War Museum and captured spy ship USS Pueblo.”.

U.S. President Donald Trump and North Korean leader Kim Jong Un have met twice in the past year to discuss denuclearization while North and South Korea are planning for a joint Olympics bid in 2032.

Relations between the North and South greatly improved last year, with South Korean President Moon Jae-in meeting his North Korean counterpart Kim Jong Un at several summits.

North Korea had for years pursued nuclear and missile programs in defiance of U.N. sanctions but the neighbors moved to thaw relations in 2018.

“I would do it again. It was totally worth it,” Jaeger, a 2014 Sochi Olympic participant, told Reuters.

“I met so many different people. I know it from my 12-year career as a skier. Sports really has no borders.”