John Bolton, former national security advisor under the first Donald Trump administration, warned that U.S. isolationism is expected to further intensify as Trump returns to office for a second term.

In an interview with Japanese daily Yomiuri Shimbun a day before the election on Monday and published on Saturday, Bolton said if Congress fails to control Trump's power, the U.S. will likely seek isolationist policies.

Bolton said the president-elect believes that once he personally establishes good relations with a foreign leader, U.S. ties with that country also become favorable, but the reality is not quite the same.

Assessing that Trump carries the risk of being unpredictable, Bolton said it wouldn't be surprising if he visited Pyongyang soon after his inauguration in January.

Bolton said leaders of hostile states, such as Chinese President Xi Jinping or North Korean leader Kim Jong-un, could exercise more influence over the incoming Trump administration.