King Salman will undergo a treatment programme at Al Salam Palace in Jeddah for a lung inflammation, the state news agency said on Sunday, hours after he underwent medical tests.
Citing the royal court, the state news agency said the 88-year-old king would be treated with antibiotics until the inflammation subsides.
Due to King Salman's health issue, Crown Prince Mohammed bin Salman postponed a visit to Japan that had been scheduled to begin on Monday, Japan's Chief Cabinet Secretary Yoshimasa Hayashi said.
Earlier on Sunday, King Salman underwent medical tests at the royal clinics at Al Salam Palace due to "high temperature and joint pain", the state news agency said.
The king was last admitted to hospital in April for a routine checkup, state TV reported then.
King Salman, the custodian of Islam's holiest sites, became ruler of the world's top oil exporter in 2015 after spending more than 2-1/2 years as the crown prince and deputy premier.
Six killed in Swiss bus blaze after person reportedly sets themselves on fire
US says it destroyed mine-laying vessels as Trump warns Iran over strait
Britain working with allies to support shipping through Strait of Hormuz
Wildlife to replace humans on next series of UK banknotes
Five Iranian women's soccer players granted humanitarian visas in Australia
Almost 700,000 displaced after Israeli strikes on Lebanon, UN agencies say
British warship HMS Dragon departs for Eastern Mediterranean
One dead, several injured in Iranian attack on Manama building
