(CNN) Administration officials have been instructed to move forward with plans to convene a historic summit between President Donald Trump and North Korean leader Kim Jong Un in Singapore, according to two people familiar with the plans.

The decision is ultimately up to Trump, who said on Wednesday he would announce the time and location in three days.

Speaking to reporters at the White House, Trump ruled out the demilitarized zone (DMZ) that divides North and South Korea as a potential location for the talks with Kim. Singapore and the DMZ are the only two places Trump has floated in public as potential venues for the meeting.

The Southeast Asian city-state has been the preferred location among US officials, who saw its neutrality as an advantage over locations closer to Pyongyang.

The White House declined to comment on the summit's location.

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