Saudi Arabia’s Crown Prince Mohammad bin Salman, known as MBS, has postponed a scheduled visit to Japan amid concerns about his father’s health.

King Salman bin Abdulaziz Al Saud underwent medical examinations yesterday in the city of Jeddah, as he is suffering from high fever and joint pain – the Royal Court of Saudi Arabia said in a statement.

Today, the Saudi Press Agency (SPA), the official state media for Saudi Arabia, said that the 88-year-old king will undergo treatment for lung inflammation (Pneumonia).

MBS’s visit to Japan was scheduled to begin today, Monday, but has been postponed – Japan’s Chief Secretary Yoshimasa Hayashi said, cited by Reuters.

King Salman was admitted to a hospital previously in late April for routine checkups.