(Yicai Global) June 11 --Singaporean Prime Minister Lee Hsien Loong met with U.S. President Donald Trump at the presidential office here on Monday before Trump's upcoming meeting with the Democratic People's Republic of Korea (DPRK) top leader Kim Jong Un.

Both sides exchanged views on the historic summit between Trump and Kim.

Meanwhile, diplomats of U.S. and DPRK delegations are discussing behind doors here on Monday, trying to narrow the gap and find something mid-way before their leaders' meeting on Tuesday morning.

Trump arrived in Singapore late Sunday after attending the Group of Seven (G7) meeting in Canada.

Lee also met with Kim on Sunday night.

Kim and Trump are here for the unprecedented summit to be held at the Capella Hotel on Singapore's Sentosa Island on Tuesday, with the issues of denuclearization of the Korean Peninsula and improvement of DPRK-U.S. ties on top of the agenda.