The health condition of Singapore's founding father and long-serving former leader Lee Kuan Yew, who has been in hospital with severe pneumonia for nearly six weeks, has worsened, the government said on Tuesday.

Lee, 91, is being treated at downtown Singapore General Hospital, where he has been on a ventilator.

At the end of last month, officials said his condition was improving, but further statements said there had been no change.

"Lee Kuan Yew's condition has worsened due to an infection. He is on antibiotics. The doctors are closely monitoring his condition," the office of Prime Minister Lee Hsien Loong, the founding leader's eldest son, said in a short statement.

There appeared to be no increased activity around the hospital, but a security guard said Lee's visitors usually entered the building via a private entrance.

In a book published in 2013, Lee had said he felt weaker by the day and that he wanted a quick death.

Lee, an iconic political figure in Asia, is widely credited with transforming Singapore from a mosquito-infested swamp under British colonial rule to a thriving independent state that is now one of the world's financial power houses.

Although he has receded from the public and political scene, his health is watched closely as he is still seen as an influential figure for the current government.

The Singapore dollar pared gains immediately after news of Lee's worsening health condition.

Lee Hsien Loong followed in his father's footsteps in 2004, becoming the city-state's third prime minister. He himself was discharged from hospital on Feb. 18 after a successful surgery to treat prostate cancer.

Lee Kuan Yew, a Cambridge-educated lawyer, had a central role in building Singapore into one of the world's wealthiest nations on a per capita basis with a strong, pervasive role for the state and little patience for dissent.

He co-founded the People's Action Party (PAP), which has ruled Singapore since 1959 and led the newly born country when it was separated from Malaysia in 1965. Lee stepped down as prime minister in 1990.

In the last election in 2011, the party won 93 percent of the seats despite its support sliding to around 60 percent of the popular vote. Many voters complained about the high cost of living and a rise in immigration.

News of Lee's fading health prompted an outpouring of support on social media.

"For all his work and belief for and in us as a nation, we can only pray for his stability of health, and continue to carry on his profound legacy of building a better nation from all he has taught us," Darius Lim wrote on the prime minister's Facebook page.

•Text courtesy of Reuters. Photo shows Yew

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