North Korean authorities are barring foreigners from this year's Pyongyang marathon, a popular tourist event, due to ongoing Ebola travel restrictions.

Nick Bonner, co-founder of Beijing-based Koryo Tours, a tour agency that specializes in North Korea travel, said more than 400 foreign runners had signed up with his agency alone for the event, which is to be held April 12. He said he was informed by officials on Monday that the race would be open only to local runners.

Though no cases of Ebola have been reported anywhere near North Korea, the country shut its borders to foreign tourists in October with strict regulations to keep the virus out. North Korean media have suggested Ebola was created by the U.S. military as a biological weapon.