The friendship between Singapore and the United States "has never been stronger than it is right now", President Donald Trump said after hosting Prime Minister Lee Hsien Loong at the White House.
"Singapore is one of our closest strategic partners in Asia," he said after a four-eye meeting with PM Lee and a working lunch which included Vice-President Mike Pence and ministers from both sides.
"The US-Singapore relationship has made both of our peoples far more prosperous and secure, and our values have made us longstanding friends. We are fortunate to have such a wonderful and loyal partner."
Both Mr Trump and PM Lee also spoke of the robust and enduring relationship between the two countries and of their commitment to build on these ties in statements made on Monday at the Rose Garden of the White House.
PM Lee said: "It is a deep and wide relationship with substantial cooperation in economic, defence and security spheres. We also discussed what more we could do to take it forward."
They also witnessed the signing of a US$13.8 billion (S$19 billion) agreement between Singapore Airlines (SIA) and Boeing for 39 new planes.
Mr Trump, who said the deal would create some 70,000 jobs, also noted that Singapore's commitment to the rule of law, intellectual property protection and to being fair and reciprocal had attracted more than 4,000 US companies to Singapore.
PM Lee said the aircraft deal would enable SIA to further modernise its fleet.
He also thanked the US for hosting more than 1,000 Singapore Armed Forces (SAF) personnel each year in detachments in Arizona, Idaho, Oklahoma and Texas.
Mr Trump, in turn, thanked Singapore for deploying its Texas-based Chinook helicopters for relief efforts after Hurricane Harvey, and for Singapore's help after the USS John S. McCain collided with a tanker off Singapore in late August.
PM Lee replied: "We are glad to have been of some help to our very gracious hosts."
PM Lee also announced that Singapore will extend its deployment of SAF assets and personnel to the global coalition against the Islamic State in Iraq and Syria terror group into next year.
Defence Minister Ng Eng Hen said in Manila, after meeting his US counterpart James Mattis, that Singapore will continue to contribute a KC-135R tanker aircraft, an Imagery Analysis Team and a medical team for an additional year.
In Washington, Mr Trump and PM Lee also discussed regional security.
"Our two nations also share an unwavering commitment to countering the North Korean threat and promoting freedom of navigation in the South China Sea," said Mr Trump.
PM Lee said Singapore strongly opposes the nuclearisation of the Korean peninsula, as it affects the region's peace and stability.
He shared what Singapore had done to pressure and isolate North Korea, but said there is no quick and easy solution.
"Pressure is necessary, but so is dialogue. The US will need to work with others, including China, South Korea and Japan, and Russia, to resolve the issue," he said.
PM Lee's visit comes ahead of Mr Trump's first trip to Asia.
The Prime Minister said that he hopes the US will maintain good relations with China as this will enable countries in the region to enjoy peace and prosperity.
He also looked forward to seeing Mr Trump at next month's Asia-Pacific Economic Cooperation summit in Vietnam, and at the Asean and East Asia summits in the Philippines, saying: "His presence in Asia will mean a lot to America's many friends and allies in the region, and it will open doors and develop markets for US exporters and investors."
Mr Trump accepted PM Lee's invitation to visit next year, when Singapore chairs Asean and hosts its annual meetings.
PM Lee later met Treasury Secretary Steve Mnuchin, and they reaffirmed the strong and mutually beneficial Singapore-US trade and investment links, as well as the importance of continued US economic engagement of the Asia-Pacific.
Today, PM Lee speaks at the Council on Foreign Relations and meets key congressional leaders.