North Korea has successfully created a miniaturized nuclear weapon designed to fit inside its missiles, NBC News confirmed Tuesday, citing a U.S. intelligence official.

The Washington Post first reported the development Tuesday, citing a confidential intelligence assessment.

The development marks a major step in the isolated nation's push to become a nuclear power. Miniaturizing a weapon does not necessarily mean that North Korea has an accurate nuclear-equipped intercontinental ballistic missile, yet.

It raises the stakes for President Donald Trump and other world leaders, who already faced difficult and limited options in dealing with Pyongyang's aggression.

The U.N. Security Council on Saturday unanimously put new sanctions on North Korea over its continued missile tests. The country has tested two intercontinental ballistic missiles that landed off the coast of Japan this year. Some analysis has said one of those missiles could potentially reach the mainland United States.

Neither the Defense Intelligence Agency, which put together the analysis the Post cites, nor the White House immediately responded to CNBC's requests for comment.

Read the full Post report here.