"I think there is a growing concern about North Korea". Seoul's foreign ministry responded by saying that looking at the overall context, Tillerson has stated that there's NO imbalance between Washington's relationship with South Korea and Japan.
He called the nuclear weapons of the DPRK "treasured sword of justice" and the "most reliable war deterrence to defend the socialist motherland and the life of its people". Speaking in a March 18 interview with a journalist from the conservative-leaning United States website Independent Journal Review who was accompanying him on his tour, Tillerson said Japan was "our [the US's] most important ally in the region", while describing South Korea as an "important partner relative to stability of Northeast Asia".
"We are exploring a new range of diplomatic, security and economic measures".
"If the businessmen-turned U.S. authorities thought that they would frighten [North Korea], they would soon know that their method would not work", he said.
Spokesperson Sean Spicer issued the stunning warning to supreme leader Kim Jong-un in reaction to his latest rocket engine test on Sunday.
The top United States diplomat indicated a need for tougher UN Security Council sanctions on North Korea's nuclear programme and other weapons of mass destruction. It conducted two nuclear test explosions and 24 ballistic missile tests previous year.
Defence chiefs fear the high-powered engine could be used to fire intercontinental ballistic missile capable of reaching U.S. shores. In contrast, Tillerson said that "attention on South Korea early in this [Donald Trump] administration has been dominated by the actions of North Korea".
"Any chance for dialogue must be seized, as long as there's hope", Foreign Minister Wang Yi said in Beijing.