SINGAPORE, June 2 (Xinhua) -- U.S. Secretary of Defense James Mattis said on Saturday that discussion about redrawing or reducing U.S. military footprint on the Korean Peninsula will not come up in talks with the Democratic People's Republic of Korea (DPRK).

Mattis made the remarks at the 17th Asia Security Summit, commonly known as the Shangri-la Dialogue, which opened in Singapore Friday and runs through Sunday.

Any discussion about the number of U.S. troops in South Korea is subject to South Korea's invitation and the discussion between Washington and Seoul, which is "separate and distinct from the negotiations that are going on with the DPRK," Mattis said at the question-and-answer session after a speech.

"That issue is not on the table here in Singapore on (June) the 12th, nor should it be," he said.

However, he said that "if the diplomats can do their work, if we can reduce the threat, if we can restore confidence building measures with something verifiable, then of course these kinds of issues can come up subsequently between (South Korea and the United States)."

U.S. President Donald Trump said on Friday that he will meet with DPRK top leader Kim Jong Un on June 12 in Singapore as originally scheduled after recent twists and turns.

In a separate session of the Shangri-la Dialogue on the same day, South Korean Defense Minister Song Young-moo also said the U.S. forces in his country are a separate issue from the Korean Peninsula nuclear issue.