KUALA LUMPUR, Malaysia (AP) — Two-time former Malaysian Prime Minister Mahathir Mohamad has been hospitalized after testing positive for COVID-19.

His office says 97-year-old Mahathir was admitted to the National Heart Institute for observation for a few days as advised by his medical team. It didn’t provide further details on his condition.

Once the world’s oldest leader, Mahathir has had two coronary bypass surgeries but remains robust and sharp witted.

Earlier this year, he was admitted several times to the same hospital. Mahathir ruled Malaysia for 22 years until his retirement in 2003.

Spurred by anger over government corruption, he led the opposition to an election victory in 2018 that was Malaysia’s first peaceful transfer of power since its independence in 1957.