South Korea's spy agency has been working to figure out whether Kim Jong Un has a secret son, who may be older than the daughter who is expected to be the heir.
The Senate had already passed an extension of the so-called HEAR Act, which is scheduled to expire at the end of the year. The bill now heads to President Trump’s desk.
Seoul's assessment comes as North Korea is preparing to hold its biggest political conference later this month, where Kim is expected to outline his major policy goals for the next five years.