White House

Barack Obama warned Donald Trump about one very specific problem and it looks like it’s North Korea

This undated picture released from North Korea's official Korean Central News Agency (KCNA) on June 23, 2016 shows a test launch of the surface-to-surface medium long-range strategic ballistic missile Hwasong-10 at an undisclosed location in North Korea.
KCNA | AFP | Getty Images

The outgoing Obama administration has told Donald Trump's transition team that North Korea is the top national security issue, The Wall Street Journal reported, citing people familiar with conversations.

Officials, who have grown increasingly concerned about North Korea's nuclear weapons program, are now pushing for a more assertive response, the Journal said.

CNBC previously reported that North Korea's nuclear capability may be the No.1 foreign policy threat for the incoming Trump administration. Michael Flynn, Trump's national security adviser, said the issue will be given a high priority under the new administration, Reuters reported last week citing a South Korean official who spoke with Flynn.

U.S. and China have already agreed on new U.N. sanctions to impose on the isolated communist state in the wake of its September nuclear test, Reuters reported on Wednesday citing a senior Security Council diplomat. The measures would include a crackdown on North Korea's coal exports and targeted sanctions of a global travel ban and asset freeze, the diplomat told Reuters.

Read the full report in The Wall Street Journal.