People lay flowers and well-wishing cards at Singapore General Hospital, Singapore, March 20, 2015. Singapore's Prime Minister Office (PMO) on Friday released a statement that Singapore's Former Prime Minister Lee Kuan Yew remained critically ill in the intensive care unit (ICU). Singapore's Prime Minister Lee Hsien Loong thanked the public for their support and good wishes. [Photo/Xinhua]

SINGAPORE -- Singapore's former Prime Minister Lee Kuan Yew's condition has "worsened", the Prime Minsiter's Office (PMO) said Saturday in its latest press release.

Lee, 91, has been in hospital since Feb. 5 with severe pneumonia.

On Feb. 28, the PMO said his condition had improved slightly but remained on antibiotics. It also said the founding prime minister continued to be sedated and on mechanical ventilation.

Lee co-founded the ruling People's Action Party and became the premier of the newly-born republic in 1965. He stepped down as prime minister in 1990.