Lee Kuan Yew, the statesman who transformed Singapore from a small port city into a wealthy global hub, has died at the age of 91.

The city-state's prime minister for 31 years, he was widely respected as the architect of Singapore's prosperity.

But he was criticised for his iron grip on power. Under him freedom of speech was tightly restricted and political opponents were targeted by the courts.

A state funeral will be held on 29 March, after a week of mourning.

Mr Lee oversaw Singapore's independence from Britain and separation from Malaysia. The announcement of his death came in the early hours of Monday.

"The prime minister is deeply grieved to announce the passing of Mr Lee Kuan Yew, the founding prime minister of Singapore," the office of Prime Minister Lee Hsien Loong, Mr Lee's son, said in a statement.

Mr Lee died peacefully at Singapore General Hospital at 03:18 local time on Monday (19:18 GMT on Sunday), it said.

He had been in hospital for several weeks with severe pneumonia.

United Nations Secretary General Ban Ki-moon said he was "deeply saddened" by Mr Lee's death and offered his condolences to the people of Singapore.

'Incalculable contributions'

A charismatic and unapologetic figure, Mr Lee co-founded the People's Action Party (PAP), which has governed Singapore since 1959, and was its first prime minister.

The PAP said in a statement on Facebook: "While we mourn the passing of one of the greatest leaders of our party, we celebrate his incalculable contributions to Singapore and its people."

Singapore's President Tony Tan has written an open letter of condolence in which he describes Mr Lee as "the architect of our modern republic".

Mr Lee, a Cambridge-educated lawyer, led Singapore through merger with, and then separation from, Malaysia - something that he described as a "moment of anguish".

Speaking at a press conference after the split in 1965, he pledged to build a meritocratic, multi-racial nation.

But tiny Singapore - with no natural resources - needed a new economic model.

"We knew that if we were just like our neighbours, we would die," Mr Lee told the New York Times in 2007.

"Because we've got nothing to offer against what they have to offer. So we had to produce something which is different and better than what they have."

Mr Lee set about creating a highly-educated work force fluent in English, and reached out to foreign investors to turn Singapore into a manufacturing hub.

The city-state grew wealthy and later developed into a major financial centre.

But building a nation came with tight controls - and one of Mr Lee's legacies was a clampdown on the press.

These restrictions remain today. In 2014, Singapore stood at 150 in the Reports Without Borders World Press Freedom Index, below countries like Russia, Myanmar and Zimbabwe.

Dissent - and political opponents - were ruthlessly quashed. Today, Mr Lee's PAP remains firmly in control. There are currently six opposition lawmakers in parliament.

Other measures, such as corporal punishment, a ban on chewing gum and the government's foray into matchmaking for Singapore's brightest - to create smarter babies - led to perceptions of excessive state interference.

But Mr Lee remained unmoved.

"Whoever governs Singapore must have that iron in him. Or give it up," he told a rally in 1980. "I've spent a whole lifetime building this and as long as I'm in charge, nobody is going to knock it down."