Singapore Prime Minister Lee Hsien Loong again warned the U.S. and China to de-escalate tensions, saying both powers presumed incorrectly they would win in any conflict.

"The reality is, neither side can put the other one down,” Lee said on Tuesday, speaking by video link to the Aspen Security Forum. "I think that is a possible misunderstanding on both sides.”

The U.S. is not in terminal decline, as some in Beijing believe, Lee said. Equally, "China is not going to disappear. This is not the Soviet Union.”