He is currently admitted to hospital and kept under observation.

"Dr Mahathir has been admitted to the National Heart Institute for observation for the next few days as advised by the medical team," his office said in a statement as quoted by The Star.

He had served as the fourth and seventh prime minister of Malaysia.

He held office from July 1981 to October 2003 and later from May 2018 to March 2020 for a cumulative total of 24 years, making him the country's longest-serving prime minister.