Tharman Shanmugaratnam took the oath as Singapore's ninth president at Istana, the country's presidential palace.
In the inauguration speech, Tharman said on Thursday evening that he was honoured and humbled to have been elected and will discharge his duties diligently and faithfully.
The President also stressed building a more inclusive society and deepening Singapore's partnerships with the international community, Xinhua news agency reported.
Singaporean Prime Minister Lee Hsien Loong congratulated Tharman on winning the presidential election and pledged the full support of the government to the President.
Tharman was elected the President after garnering 70.4 per cent of the total votes. He used to be the senior Minister and Deputy Prime Minister of the city-state.
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