Foreign runners will not be allowed to compete in the annual Pyongyang marathon this year as North Korea is limiting participation to its own citizens, The Associated Press reported. The decision was apparently made over concerns over the Ebola virus, which North Korean state media have suggested was created by the U.S. military as a biological weapon.

Travel agencies who specialize in tours to the isolated country and market the Mangyongdae Prize International Marathon as an exotic race had to inform hundreds of foreign runners of the cancellation. North Korea has some of the strictest Ebola regulations in the world, even though no case of the disease has been reported been anywhere near the country.

In compliance with Ebola measures announced in October, North Korean missions are no longer giving out visas for nonessential travel, and all visitors to the Communist country are technically subject to quarantine under medical observation for 21 days. That includes diplomats and international aid workers, who are allowed to stay in their residences or diplomatic compounds.

In 2003, North Korea had suspended foreign tours for three months because of fears over the spread of SARS. The extreme rules have proved difficult for travel agencies, such as New Jersey-based Uri Tours, owner Andrea Lee noted.

"We have not been able to run tours for several months," she said. "As a small business, it's been a difficult time. ... We expect tours to resume at the latest by the summer."

Koryo Tours, meanwhile, informed customers about the latest cancellations on its website.

"We are sorry to announce that we have been informed by our partners in North Korea that no foreign runners -- amateur or professional -- will be allowed to participate in this year's Pyongyang Marathon," the Beijing-based travel agency announced.

Koryo Tours and Young Pioneer Tours, another agency organizing trips to North Korea, both said they had been informed of the decision on Monday morning, according to the Sydney Morning Herald.