South Korea's presidential office says that a trilateral summit between the two Koreas and the U.S. is linked to the outcome of a possible summit between Washington and Pyongyang.

A senior presidential official told reporters on Thursday that the trilateral summit is an issue that could be decided at the US.-North Korea summit. 

The official said that South Korea does not intend to prepare for the three-way summit in advance, adding it will begin preparations should it receive a related notice from North Korea and the U.S.

The comment came after the top office was found to have dispatched personnel to Singapore to lay the groundwork for a possible visit by President Moon Jae-in himself.

The presidential office explained that the trip was to arrange for Moon's summit with Singaporean Prime Minister Lee Hsien Loong, set for July, but sparked speculation that Moon may join the upcoming U.S.-North Korea summit for a three-way formal declaration of an end to the Korean War.