In recent weeks, however, Mr. Trump has suggested that he might be willing to hold direct talks with Mr. Kim. He also voiced his support for the political thaw between North and South Korea, which have agreed to march their athletes together under one flag at the Winter Olympics in South Korea in February.
The United States has been working systematically to undermine North Korea’s nuclear ambitions by curbing the financing behind its weapons program.
This week, Sigal Mandelker, Treasury’s under secretary for terrorism and financial intelligence, traveled to Asia to hold talks with officials in Beijing, Hong Kong, Tokyo and Seoul about ways to combat North Korea’s illicit financing and money laundering practices. During a stop in Hong Kong on Wednesday, she urged the Chinese to do more to crack down on shell companies that North Koreans set up in other countries and use to evade sanctions.
In testimony before Congress last week, Ms. Mandelker noted that North Korea has been using cover representatives and front companies to hide and transfer funds that finance its weapons program.
Sanctions experts have suggested that the United States faces limited options targeting North Korea’s illicit financing schemes because of the broad swath of sanctions that already have been imposed on the isolated Asian nation. The designation on Wednesday of two Chinese trading companies, Beijing Chengxing Trading Co. Ltd. and Dandong Jinxiang Trade Co., Ltd., signals that the Treasury Department is looking more broadly for ways to squeeze North Korea.
“The Chinese trading companies that were targeted are the most interesting,” said Mike Casey, a sanctions expert at the law firm Kirkland & Ellis International. “Even though the U.S. hasn’t been able to get a ton of direct economic pressure on North Korea, it certainly hasn’t given up on exerting indirect economic pressure on North Korea.”
The sanctions enable the United States to freeze the assets of the people or businesses that are designated and blocks Americans from doing business with them.
On Wednesday, Japan said that a military plane had spotted a North Korean tanker and a Dominican-registered tanker side by side in the East China Sea on Saturday, apparently transferring cargo. Yasutoshi Nishimura, the deputy chief cabinet secretary, on Thursday called that a sign that fuel sanctions were working, in that the North had been forced to go outside normal methods to obtain fuel.