Winter Olympics chiefs in South Korea have called in 900 soldiers and placed 1,200 staff in quarantine following an outbreak of norovirus on the eve of the Games.
More than 30 private security staff required hospital treatment for the illness and others also reported symptoms including vomiting and diarrhoea.
Officials in Pyeongchang, where the Games officially begin on Friday, have placed all other security staff in isolation and indefinitely replaced them with military personnel.
“I would like to apologise for this,” said Lee Hee-beom, the president of the organising committee. “Our disease control centre [and] other related government agencies here are now discussing countermeasures.”
Hand sanitiser has been distributed to minimise the risk of spreading norovirus, which also broke out during last year’s World Athletics Championships in London.
“Very stringent measures are in place when it comes to food and beverages,” said Games spokesman Christophe Dubi. “As soon as a case is reported then all the area gets disinfected.”
While the opening ceremony in Pyeongchang takes place on Friday, the first heats of the biathlon, luge and ski jumping begin on Wednesday. The Games conclude on 25 February.