Washington is closely following reports of an explosion in North Korea, and says it would be "very sad" if the reports are true.

U.S. State Department spokesman Richard Boucher said Thursday that Washington would express its sympathy to whoever and how many may have been hurt.

Asked if there is any assistance the U.S. can offer in the situation, Boucher said Washington has always been willing to help the people of North Korea with humanitarian needs.

Meanwhile, James Lilley, a former U.S. ambassador to South Korea and to China, pointed out that such incidents as the recent explosion happen frequently in the North, citing the communist state's fast deteriorating infrastructure.

John Wolfsthal of the Carnegie Endowment for International Peace told Fox News that if the incident was an assassination attempt against the North Korean leader, it was a poor one.