Saudi Arabia has warned pilgrims coming from across the world to wear face masks in crowded places to protect against a new respiratory virus which has killed 38 and infected 65.
The Gulf-state's health ministry on Friday urged elderly and chronically ill Muslims to postpone their pilgrimage.
The ministry issued a list of recommendations on its website, which it said to be "preventive measures special to the MERS (Middle East Respiratory Syndrome) coronavirus". Saudi Arabia is the epicentre of the MERS virus.
The statement does not set an age limit, and it does not state if the recommendation implies that no visas will be issued for such pilgrims.
The main pilgrimage season begins in October this year but hundreds of thousands also visit the kingdom during the holy month of Ramadan, which began on July 10.
The World Health Organisation has not recommended any MERS-related travel restrictions, but has said countries should monitor unusual respiratory infection patterns.
The first recorded MERS death was in June last year in Saudi Arabia. Recently, the country announced two deaths on Sunday, bringing the number of deadly cases to 38 in the kingdom.
According to the WHO, those figures represent the majority of people affected worldwide; 81 cases of infection and 45 deaths.
Experts are struggling to understand MERS. The new virus is related to SARS, which killed about 800 people in a global outbreak in 2003. It belongs to a family of viruses that most often cause the common cold.
Like SARS, MERS appears to cause a lung infection, with patients suffering from fever, coughing and breathing difficulties. But it differs in that it also causes rapid kidney failure.