KUALA LUMPUR, Dec 16 — Tun Dr Mahathir Mohamad has been admitted into the National Heart Institute (IJN) here, according to a statement released by the hospital today.

In a statement, IJN said the former prime minister was admitted at 7pm and is expected to be in the hospital for the next few days.

"He shall be undergoing a full medical check-up and further observation,” read the statement.

Dr Mahathir has a history of illnesses relating to his heart. He had his first heart attack in 1989, when he was 64 years old.

Then in 2006, he had two more heart attacks, and a year later underwent a quadruple bypass surgery.

The last time Dr Mahathir was hospitalised was on February 10, 2018, also at IJN — due to a chest infection.