Lee, 91, the country's first Prime Minister passed away peacefully at the Singapore General Hospital in the wee hours of today after being in intensive care for pneumonia since February 5.
Prime Minister Lee Hsien Loong, who is also Lee's eldest son and Singapore's third Premier, declared a period of national mourning from March 23 to 29.
Prime Minister Lee issued a statement before dawn announcing the passing of his father.
"He fought for our independence, built a nation where there was none, and made us proud to be Singaporeans. We won't see another like him," he said in an emotional TV address.
Glowing tributes for Lee from world leaders started streaming in with US President Barack Obama praising Lee as a visionary and a "true giant of history".
"A visionary who led his country from Singapore's independence in 1965 to build one of the most prosperous countries in the world today, he was a devoted public servant and a remarkable leader," Obama said.
UN secretary-general Ban Ki-moon called Lee a "legendary figure in Asia".
Remembering Lee, UK Prime Minister David Cameron said, "Lee personally shaped Singapore in a way that few people have any nation. He made his country into one of the great success stories of our modern world. That Singapore is today a prosperous, secure and successful country is a monument to his decades of remarkable public service."
Cameron said Lee was always a friend to Britain, sometimes a critical one, and many British Prime Ministers benefited from his wise advice.
Chinese President Xi Jinping praised Lee as an "old friend of the Chinese people".
Xi said Lee, who was ethnically Chinese, was "widely respected by the international community as a strategist and a statesman".
