US urges China to pressure North Korea

US Secretary of State Rex Tillerson has urged China to help pressure North Korea to rein in its weapons programs.

"[China has a] diplomatic responsibility to exert much greater economic and diplomatic pressure on the regime if they want to prevent further escalation in the region," he said in Washington. Tillerson said North Korea was the "top security threat" to the US.

Tillerson made the comments at a press conference after high-level talks with Chinese officials at the State Department.

Read more: Trump 'furious' over Seoul's North Korea 'appeasement'

Read more: North Korea attempts to split South Korea-US security alliance

Defense Secretary Jim Mattis vowed at the same press conference to "continue to take necessary measures to defend ourselves and our allies" against North Korea, which is working to develop a nuclear-tipped missile capable of hitting the US.

The meeting of top US and Chinese diplomats and defense chiefs came just a day after US President Donald Trump said China's efforts to use its leverage with Pyongyang had failed.

On Tuesday, Trump posted a tweet suggesting Chinese President Xi Jinping's efforts were ineffective, a message he reiterated before supporters in Iowa.

"I do like President Xi," he told the crowd Wednesday evening. "I wish we would have a little more help with respect to North Korea, from China. That doesn't seem to be working."

Trump did not elaborate on what might happen next if China fails to rein in its ally.

Complicated position

Trump's approach to North Korea was further complicated by the death of American university student Otto Warmbier earlier this week, after he was recently released in a comatose state 17 months after being jailed in Pyongyang.

Read more: Otto Warmbier, US student released from North Korea, dies

In Beijing, officials insisted they have not given up hope of influencing Pyongyang.

"To resolve the Korean peninsula nuclear issue, China has been making unremitting efforts and we have been playing an important and constructive role," said Geng Shuang, a foreign ministry spokesman, while stressing China was not the "focus and the crux" of the crisis.

Tillerson said Trump would make a state visit to China later this year, and Mattis said both sides had agreed to expand military-to-military ties.

A US official said on Tuesday that spy satellites had detected new movements at North Korea's nuclear test site, but it was unclear if Pyongyang was preparing for a sixth nuclear test.

North Korea hits back, labels Trump a 'psychopath'

The North Korean regime on Thursday sought to stoke tensions and take advantage of the US' difficult position by calling Trump a "psychopath" and warning South Korea against following Washington's lead. 

Pyongyang's official Rodong Sinmun newspaper said that "South Korea must realize that following psychopath Trump...will only lead to disaster."

The newspaper also claimed that the US president was toying with the idea of a preemptive strike on the North as a means of diverting attention from the political crisis he faces at home.

North Korea has carried out a number of atomic and ballistic missile tests since last year, ratcheting up tensions with its regional neighbors and the US.

aw/cmk (AFP, dpa)