Singaporeans wept and world leaders paid tribute Monday as the Southeast Asian city-state mourned the death of its founding father Lee Kuan Yew.

The government announced that Lee, 91, "passed away peacefully" early Monday at Singapore General Hospital. An increasingly frail Lee was hospitalized in February with severe pneumonia.

State television broke away from regular programming with a hagiographic tribute to Lee's life. In a live broadcast, one of its reporters called Lee's death the "awful and dreaded" news.

Lee commands immense respect among Singaporeans, who this year will celebrate the country's 50th anniversary of independence. He led Singapore with an iron grip for more than three decades until 1990, and is credited with transforming the resource poor island into a wealthy bustling financial hub with low crime and almost zero corruption.

At the hospital where Lee spent the last weeks of his life, 55-year-old Maligah Thangaveloo cried as she clasped her hands in prayer before an expansive array of flowers and cards left by Singaporeans. Calling Lee "father," she recalled shaking hands with him as a nine-year-old when he visited her school.

President Barack Obama called Lee a "visionary" in a statement, saying he was "deeply saddened" to learn of his death. Obama, who met Lee during a visit to Singapore in 2009, said his "remarkable" leadership helped build "one of the most prosperous countries in the world today."

Singapore's success meant that Lee's counsel was sought by political leaders around the world, Obama said, adding that Lee was "hugely important in helping me reformulate our policy of rebalancing to the Asia Pacific.".

The Singapore government has declared seven days of national mourning and flags will fly at half-mast on state buildings. A private wake for the family, which includes Lee's son, the current prime minister Lee Hsien Loong, will be held Monday and Tuesday. A state funeral is scheduled for Sunday.

Sayeed Hussain, an IT executive, said Lee was a "great hero" to Singaporeans as he paid respects at Singapore General Hospital.

"It is our duty to respect him and recognize him as a great hero in the world," said Hussain. "This is our last chance to do so, one of the last places for him."

Under Lee and his successors, Singapore was known around the world for its strict social order including a ban on chewing gum, restrictions on free speech and canings for crimes some countries would rule as minor. In recent years, it has become socially more liberal and the fragmented political opposition made gains in Singapore's last elections in 2011.

After stepping down as prime minister, Lee remained part of the Cabinet and an influential figure in Singapore and the region.

Australian prime minister Tony Abbott said Lee was a "giant of our region."