Malaysia's former prime minister Mahathir Mohamad has been admitted to hospital in Kuala Lumpur just a week after undergoing a minor operation.
A spokesperson said the 96-year-old was taken to the cardiac care unit at the National Heart Institute.
It is the third time the man who was once the world's oldest leader has been hospitalised in just over a month.
A large group of reporters was gathered outside the hospital, waiting for updates.
His family released a statement late on Saturday to say he was in a stable condition and "responding well to treatment" after two days in hospital.
Dr Mahathir, who remains an active politician as MP for Langkawi despite ending his second term as prime minister two years ago, underwent what was described as a successful elective medical procedure last week.
A month earlier, he was admitted and discharged after six days in hospital when his doctors said they were satisfied with the results of tests into his health.
Dr Mahathir underwent two heart bypass surgeries in 1989 and 2007.
He served as the fourth and seventh prime ministers of Malaysia, for a cumulative total of 24 years — more than any other leader of the nation.
Dr Mahathir assumed office for the second time in 2018 at the age of 92, taking over from scandal-plagued Najib Razak.
He had repeatedly called for his one-time protege to resign over the 1MDB corruption scandal, as part of the Bersih ("clean" in Malay) movement, which promised to clean up Malaysian politics.
But his return to the role of prime minister lasted less than two years after his government collapsed due to infighting, meaning that a planned handover to former deputy leader Anwar Ibrahim would never happen.
After the setback, Dr Mahathir formed a new ethnic Malay party in 2020 to oppose the new leadership.
During his first term as prime minister — between 1981 and 2003 — Dr Mahathir famously clashed with then Australian prime minister Paul Keating.
Mr Keating called Dr Mahathir "recalcitrant" after the latter had boycotted the first APEC summit in the US city of Seattle.
Almost two decades later in his 2011 autobiography, Dr Mahathir agreed that it was a fair description of him.
"When Keating called me recalcitrant I was not angry — he was just saying that I was refusing to fall in line with everybody else and that description generally applies quite well to me … I don't always do what others do [and] most Malaysians like this side of me," he wrote.
ABC/wires
