SINGAPORE, March 22-- Singapore's Prime Minister Lee Hsien Loong joined well-wishers for his ailing father Lee Kuan Yew at Singapore General Hospital on Sunday.

The premier arrived at the designated area outside Block 7, known as the Quad of the hospital, to pray for the country's founding father and former prime minister, and thanked well- wishers there.

Concerns have been mounting over the health of 91-year-old Lee Kuan Yew, who has been critically ill, with many well-wishers visiting the hospital, Tanjong Pagar Community Club and Teck Ghee Community Club with cards and gifts.

Prime Minister Lee visited Tanjong Pagar Community Club late Saturday to thank local residents for their prayers and support.

Lee Kuan Yew has served as a Member of Parliament in Tanjong Pagar Group Representation Constituency (GRC) for 50 years, while Lee Hsien Loong is an MP of Ang Mo Kio GRC where Teck Ghee Community Club locates.