The acting USA assistant secretary of state for East Asia, Susan Thornton, told sceptical U.S. lawmakers ahead of Tillerson's trip that China appears to be on board with the plan to squeeze Pyongyang.
Later, trying to tamp down expectations, the US State Department said North Korean officials have shown no indication that they are interested in or are ready for talks regarding denuclearization.
Tillerson's remarks followed a day of meetings in Beijing, which has become increasingly more concerned with the war of words taking place between the United States and the North.
"We are probing. We have lines of communication with Pyongyang", AFP quoted the USA diplomat as saying. "We're not in a dark situation", he added.
US President Donald Trump has said he will never allow that to happen. The standoff has entered another, the more perilous stage from that point forward as North Korean leader Kim Jong Un and Trump have traded rhetoric.More news: Manchester City's Benjamin Mendy to undergo surgery for ruptured knee
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So far, the North Koreans have shown no interest in a serious negotiation.
While Tillerson has said similarly moderate things before - in August he noted North Korea's "restraint" and said the USA wanted more goodwill gestures from the regime - his latest remarks in Beijing appeared tailored for a Chinese audience.
"Our two presidents have developed a very regular and close working relationship", Tillerson told Yang. Obviously it would help for North Korea to stop firing off missiles.
We will remind, 26 September 2017, the U.S. Treasury adopted a package of sanctions against eight banks in Korea, and 26 people who, according to the American Department, were associated with "financial networks" of the DPRK. The White House is in direct contact with North Korea, said Me Tillerson in a rare top-level acknowledgement.
Trump has repeatedly urged Xi to exert more economic pressure on Pyongyang to convince the renegade regime to give up its nuclear ambitions. President Trump is to visit China in November as part of his tour of five Asian nations.