Trump wrote on Twitter.
"To make it clear, we are the biggest victim of this incident and there would be no more foolish judgment than to think we do not know how to calculate gains and losses", the spokesman said. "He's signaling to others that he understands this isn't working, and he's trying to defend himself, or justify himself, by saying that at least they tried as opposed to others who didn't even try".
The meeting was reported by China's foreign ministry.
Mattis says China shares the US desire for denuclearization of the Korean Peninsula, and "continues to work this issue".
Beijing, which wants resumed USA negotiations with North Korea, was hoping for "positive outcomes" from Wednesday's dialogue, Chinese foreign ministry spokesman Geng Shuang said. His family is blaming North Korea for "awful, torturous mistreatment".
Seoul was in close consultation with Washington over the matter, the official added.
Moon was elected in May pledging to take a more moderate approach to the North and engage the reclusive country in dialogue, in addition to pressure and sanctions to impede its defiant pursuit of nuclear weapons and ballistic missiles.
It's also essential to get North Korea to open communication channels, he said.
The Wall Street Journal reported on Sunday (June 18) that United States diplomats have held discussions for more than a year with North Korea's top nuclear negotiator, focused on freeing American prisoners.
A cause of death hasn't been determined for a 22-year-old college student who was detained for almost a year and a half in North Korea before being sent home in a coma, an OH coroner's office said Tuesday.
The article also criticized South Korea for using Warmbier's case to seek the release of other detainees, including six South Korean citizens.
"What happened to Otto is a disgrace". It said his medical records from an air ambulance service that brought him to OH and from the University of Cincinnati Medical Center, where he was hospitalized until his death Monday, have been reviewed, and the treating physicians have been interviewed extensively.
Ohio's Republican U.S. senator said Wednesday he had a secret meeting with North Korean officials in NY last December to press for Warmbier's release. Sen.
In a news conference before Warmbier's death, they said they could not speculate on the cause of his condition. On Tuesday, Thornton cited Chinese restrictions on imports of North Korean coal as "notable" progress.
Tillerson said Wednesday that China had a "diplomatic responsibility to exert much greater economic and diplomatic pressure on the regime if they want to prevent further escalation in the region".
Chinese officials were not immediately available for comment after the talks.
Trump is counting on China's leverage with Kim Jong Un's regime which has always been threatening that its nuclear-tipped missile can strike the U.S. mainland.
Warmbier was returned to the United States last week in a coma.
China's efforts to rein in North Korea's nuclear programme have "not worked" out, US President Donald Trump has said but appreciated Beijing for its attempts.