Singapore's Prime Minister Lee Hsien Loong (R) looks at tributes written to his father, the late former prime minister Lee Kuan Yew outside the Istana in Singapore, March 24, 2015. [Photo/IC]

SINGAPORE - Singapore's Prime Minister Lee Hsien Loong spoke to visitors at the Istana Gate on Tuesday when he stopped to read some of the messages left for Singapore's founding prime minister Lee Kuan Yew.

Thousands of Singaporeans are lining up to pay tribute to Lee Kuan Yew after hearing the news of his passing away Monday.

PM Lee Hsien Loong and his wife Ho Ching spent about 10 minutes viewing the messages, cards and flowers that Singaporeans have been leaving at the Istana tribute site. He also chatted with well- wishers, and thanked them for conveying their condolences.

Earlier in the day, Singapore's President Tony Tan Keng Yam also visited the Istana tribute site to greet those leaving their condolences.