North Korea has decided to ban all foreigners who were to participate in the upcoming international marathon in April over fear of the Ebola virus spreading in the country.
Pyongyang already has one of the strictest Ebola regulations in the world though no cases of the disease have been reported in North Korea.
The latest measure will be in addition to the travel restrictions on the foreign tourists that were placed last October.
Tourist operators who are familiar with the North's programmes have confirmed Pyongyang's decision to impose more curbs.
"Our North Korean partners in Pyongyang contacted us this morning with news that the 2015 Pyongyang Marathon has - as of today - been closed to amateur and professional foreign runners," Nick Bonner, chief of China-based Koryo Tours, told Reuters in an email statement.
The North's state media report had previously suggested that the Ebola virus was created as a biological weapon by US forces to undermine Washington's adversaries.
On its website, another Chinese tourist agency, Young Pioneer Tours, which usually takes Westerners to North Korea, said: "We have been working closely with our partners in North Korea in regards to when the current Ebola travel restriction will be lifted, and tourism to the DPRK will resume as normal. We are expecting the borders to reopen very soon within the coming weeks."
"However, it has been confirmed the Pyongyang Marathon will not take place this year for tourists due to the current Ebola restriction which interfered with preparations for the marathon event."
The marathon has been an annual event for more than two decades. Foreigners were allowed to partake in the marathon for the first time last year.