Former Malaysian prime minister Mahathir Mohamad, 88, was admitted to hospital Monday with a chest infection, his office said.
"The medical team is closely monitoring his condition and is satisfied with his progress," the official Bernama news agency said, citing a statement from Mahathir's Perdana Leadership Foundation research institute.
Mahathir, however, is expected to remain in the National Heart Institute for the next few days. He is receiving treatment and physiotherapy.
Mahathir was the country's fourth and longest-serving prime minister, in office from 1981 to 2003. He remains an influential figure in Malaysian politics.
In 2010 he was admitted to a Melbourne hospital for a similar chest infection while visiting the Australian city to address a seminar.
Mahathir has undergone two coronary bypass surgeries, in 1989 and 2007.