The nonagenarian, who has a history of heart problems, was admitted to the National Heart Institute on Jan. 26 due to an unspecified infection.
Mahathir "is currently being treated and is in the process of recovering from infection", his spokesperson said, clarifying rumours on social media that his condition was serious.
The spokesperson was unable to say when he would be discharged but shared photos of the former premier sitting in a chair reading a newspaper.
Mahathir, who was Malaysia's prime minister for more than two decades, has been in and out of hospital in recent years and had undergone bypass surgeries.
He was prime minister from 1981 to 2003. He held the top post again from 2018 to 2020 after leading the opposition coalition to a historic win, but his government collapsed due to infighting.
