KUALA LUMPUR, Sep 4 (CNA) - Former Malaysian Prime Minister Mahathir Mohamad was discharged from hospital on Sunday after being admitted for COVID-19, his office said in a statement.

The 97-year-old, who served for more than two decades as prime minister and is still an active lawmaker, has a history of heart troubles. He has had heart attacks and bypass surgeries.

Mahathir, admitted to the National Heart Institute on Wednesday after testing positive for the coronavirus, will remain quarantined at home until Tuesday, the statement said.

He has received at least three doses of COVID-19 vaccine, the last known shot in November 2021, according to earlier comments from him and government officials.

The nonagenarian, a trained physician, underwent an elective medical procedure in January and was readmitted to the hospital later that month for treatment. The National Heart Institute did not say at the time what procedure he had undergone.

After serving as prime minister for 22 years until 2003, Mahathir returned as premier at the age of 92 in 2018 after leading the opposition coalition to a historic win, defeating the party that he had once led. His government collapsed in less than two years due to infighting.