Singapore - Grieving Singaporeans were joined by world leaders on Sunday to pay their final respects to the country's first prime minister, Lee Kuan Yew , as the nation came to a near-halt to honor its "founding father".

Tens of thousands of people waving flags braved heavy rain and lined the streets to catch a last glimpse of Lee as his coffin was taken by gun carriage on a 15 km procession through the streets of the country he helped build to his state funeral.

Japan's Prime Minister Shinzo Abe, India's Narendra Modi, Indonesia's Joko Widodo and former U.S. President Bill Clinton were among the leaders brushing shoulders with Lee's family and Singapore politicians at the ceremony attended by 2,200 people.

Lee, who died aged 91 on Monday, is credited with founding modern Singapore and transforming it from a small, colonial British trading port into one of the world's wealthiest nations.

His death has prompted an unprecedented show of mourning and Prime Minister Lee Hsien Loong, Lee's son, battled tears as he delivered a 40-minute eulogy in English, Malay, and Chinese.

"His was the original Singapore Roar: passionate, formidable and indomitable," he said.

"To those who seek Mr Lee Kuan Yew 's monument, Singaporeans can reply proudly: 'look around you'".

Public warning sirens sounded across the country to mark a minute's silence, with buses and trains coming to a halt.

Earlier, booms from a 21-gun salute had reverberated around the city's business district, fighter jets had flown overhead in formation and two navy ships near the marina made an 'L' 'K' 'Y' signal with their flags as Lee's coffin was taken from the country's parliament to the funeral.

Singaporeans, many dressed in the mourning colors of black and white, waited for hours to watch the procession, shouting "Lee Kuan Yew" as it passed. More than 100,000 people lined the streets to bid farewell to the departed leader.