KUALA LUMPUR - Malaysia's Prime Minister Muhyiddin Yassin has paid a visit to Tun Rahah Mohamed Noah, the widow of the country's second prime minister Abdul Razak Hussein at the Prince Court Medical Centre in the capital, Kuala Lumpur.

Tan Sri Muhyiddin called on his followers to pray for the health and recovery of Madam Rahah in a Facebook post published along with a photo showing the Prime Minister walking next to former prime minister Najib Razak in the hospital. He said he visited Madam Rahah on Thursday evening (Dec 17).

Najib, who has been sentenced to 12 years in jail over the multi-billion-dollar 1MDB corruption case and remains free pending his appeal, is the eldest of Tun Razak's five sons.

Najib's brother, former CIMB Group chairman Nazir Razak also appeared in the photo.

Madam Rahah, 87, married Mr Razak on Sept 4, 1952 and the couple have five sons, Najib, Nazir, Ahmad Johari, Mohamed Nizam and Mohamed Nazim.

In a tweet, Najib said he and his family are going through a difficult and worrying time.

"Mother is not well. I urge all of you to pray that mother is given strength to recover," he said.

Najib also thanked Malaysia's King, Sultan Abdullah Ahmad Shah, the Sultan of Perak Nazrin Shah and opposition leader Anwar Ibrahim, and other leaders for visiting his mother.

It is unclear what Madam Rahah's medical condition is and why she was admitted to the hospital.