Former US secretary of state Colin Powell added his voice to the chorus of tributes to former prime minister Lee Kuan Yew as plaudits continued to come in from a broad sweep of American leaders.

Mr Powell, who met Mr Lee on multiple occasions while serving as secretary of state under president George W. Bush, hailed the Singaporean leader's ability to "make things happen".

"It is my privilege to know him over the years and I've always respected him for his vision, his determination. Vision and determination are not as important as execution, making something happen and he was a leader who made many great things happen in Singapore. He created a nation that is one of the most influential in the world that takes care of its people, one that ensures that it plays a major role on the world stage," he said after signing the condolence book at the Singapore embassy in Washington.

Mr Powell added: "Some will say, maybe he was too tough, well maybe so but the results show. And I think the people of Singapore by the outpouring of love and support that they are showing during these difficult times is evidence of the respect in which he is held by the Singaporean people and I can also assure you it is the same kind of respect that he is held in by all of us here in the United States of America."

Earlier in the day, lawmakers from both sides of the aisle also penned their tributes in a condolence book was stationed in the Capitol building.

Senators Bob Corker, John McCain, Jack Reed and Cory Gardner and Johnny Isakson were among the first to sign the book. Mr Corker, who chairs the Senate Foreign Relations Committee, said he was fascinated by what Mr Lee was able to achieve in Singapore in such a short time.

"I know we've all been to Singapore and just seen the incredible prosperity. And it's affecting China too. In many ways China wants to emulate that and I think 22,000 people form China have been there to study how Singapore has moved ahead in the way that it has. A great leader."

Mr Isakson agreed, saying that Singapore was a "one generation miracle".

Mr McCain, in turn, placed Mr Lee alongside US statesman Henry Kissinger as the two wisest men he had the opportunity of knowing.

"We thank you for everything in his legacy that has made for a unique relationship in what are very difficult and trying times in Asia," he said.

The condolence book at the Capitol will be there until the end of Thursday.

Separately, Secretary of State John Kerry also cited Mr Lee as a key figure that helped shape his thinking. Making a speech at the Global Chiefs of Mission Conference, he said: "One of the wisest people I ever met was Lee Kuan Yew, who just passed away. And I talked to the foreign minister last night, and we will send a high delegation there, because he was deeply pro-American and deeply involved with the United States and much of our strategic thinking through that time. But his views that he shared with me as a young senator have helped to shape my thinking today as a Secretary of State."