Ramping up pressure on N. Korea top priority in high-level US-China talks: senior official

Tillerson has talked about "ramping up pressure on North Korea, and that is clearly what we're going to be pursuing with the Chinese this week as not only our strategy but the strategy of the international community to try to change the calculus on the part of the North Korean regime and make a decision to abandon its illegal ballistic missile and nuclear programs," she said.

Thornton said China has done a lot to increase pressure on the North, but should do more.

"We would like to see China do more, and we're going to be talking to them about that this week," she said. "The UN panel has designated hundreds of DPRK entities, and many of those try to get business done through China, and we're working with China to pursue those."

The US pressure campaign against the North has produced tangible results, such as countries halting visas to North Korean laborers used by the regime to earn hard currency, and denying the North's Air Koryo airline landing rights and refueling privileges, Thornton said.

The US has also seen North Korean diplomats in foreign countries expelled over suspicions that they facilitated proliferation activities, the official said.

"We are ... trying to create a global echo chamber where all countries come together behind the UN Security Council resolutions that have been developed to address North Korea's illicit weapons programs, and we are trying to get all countries to take actions to increase the pressure on North Korea through sanctions implementation and other measures," Thornton said.

"That's what we'll be focusing on in this discussion with the Chinese this week," she said.

This week's talks take place as tensions between the US and the North rose further following the release of a long-detained American college student, Otto Warmbier, and revelations he had been detained in the North for more than a year even after he fell into a coma.

Asked if the US is considering any retaliatory action, Thornton avoided a direct answer.

"We are very happy to see that Otto Warmbier has been able to return to his family in Ohio and be reunited with them," she said. "We're certainly aware that there are three other American citizens still being held by the North Korean regime, and we very much hope that they can come home soon."

Adding to the tensions was the US seizure of a diplomatic package that a delegation of North Korean officials were carrying at New York's John F. Kennedy International Airport on their way back home after attending a U.N. meeting.

Pyongyang strongly protested and demanded an explanation.

Thornton said that the incident was part of a "lawful" inspection.

"There's a lawful outbound inspection of all passengers, including persons holding diplomatic visas. So I think it's important to note that the inspected individuals in this case are not exempt from inspection at our nation's ports of entry or departure," she said.

"I understand that this was an action that was undertaken by the Department of Homeland Security, so I would refer you to them for any details. I don't have any other details of the inspection or what was found in the course of the inspection." (Yonhap)