President Trump and North Korea's Kim Jong Un will start their historic summit with a one-on-one session with only their translators. U.S. officials have said the leaders will meet for privately before holding an expanded bilateral meeting with their respective advisers.

Officials remain uncertain what will come out of Tuesday's unprecedented summit, the first of its kind between a sitting U.S. president and the leader of North Korea.

Mr. Trump has said he wants to strike a deal to get the North to give up its nuclear weapons, but he has sought to lower expectations for the meeting, saying it may be the start of a long process.

Late Sunday night, Mr. Trump took to Twitter to write "great to be in Singapore":

Great to be in Singapore, excitement in the air! — Donald J. Trump (@realDonaldTrump) June 11, 2018

This came after a flurry of tweets about disputes over U.S. trading partners, writing that "we must put the American worker first":