The United States announced on Friday that it was imposing its "largest package" of sanctions against North Korea, in a move to intensify pressure on Pyongyang to give up its nuclear and missile programs.
According to a statement on the U.S. Treasury Department's website, this is the Trump administration's most significant national security challenge, placing sanctions on one person, 27 companies, and 28 ships.
The actions block assets held by the firms in the United States and prohibit U.S. citizens from dealing with them.
North Korea's missile and nuclear program are seeking to develop a nuclear-tipped missile capable of reaching the U.S. mainland. Trump has often taunted the North Korean leader Kim Jong-un via Twitter with Kim at times responding in kind through the media.
The Treasury's Office of Foreign Assets Control announced the measures, which are designed to disrupt North Korean shipping and trading companies and vessels and isolate Pyongyang.
Treasury Secretary Steve Mnuchin said in a statement the sanctions against the ships would help prevent Kim's government from conducting "evasive maritime activities that facilitate illicit coal and fuel transports and erode its abilities to ship goods through international waters.”
The ships to be sanctioned are located, registered or flagged in North Korea, China, Singapore, Taiwan, Hong Kong, Marshall Islands, Tanzania, Panama, and Comoros, the Treasury department said.
The sanctions will also affect some Taiwanese passport holders and mainland China, Hong Kong, Taiwan, and Singapore shipping and energy firms.
The United States has led an international campaign to tighten sanctions on North Korea to force it to give up its development of weapons and missiles.