North Korea has called on the United States to actively engage in talks on declaring an end to the Korean War, which was halted in 1953 with an armistice, not a peace treaty.
"China and USA relations are at an important juncture and facing challenges", Yang said.
Kim Eui-kyeom told reporters today: 'Chairman Kim said he will "ardently welcome the pope if he visits Pyongyang"'.
He also accused the United States of making "a series of moves" on Taiwan and "other issues" that he said hurt Chinese sovereignty.
Kim said progress is being made implementing the decisions he reached with Trump in Singapore in June, according to KCNA, and expressed his gratitude to Trump, adding that agreement had been reached to hold a second summit "as soon as possible". But that wasn't an advance on comments Trump made last month in NY, when he said he wanted to meet Kim "very soon".
A spokesman for South Korean president, Moon Jae-in, said Kim also invited Pope Francis to Pyongyang.
The trade war between China and the U.S. is however being seen as a barrier to co-operation in the North Korean crisis.
As part of his delegation to Pyongyang, Pompeo brought along Stephen Biegun, his special representative to North Korea and the diplomat expected to take on more of the day-to-day negotiating with Kim's regime.
Wang appealed to Pompeo to cease actions that Beijing sees as threatening its interests in order to avoid disrupting cooperation over North Korea and other issues.
China's public show of displeasure also represented one of the strongest signs yet that the widening list of disputes between the USA and China could undermine their cooperation on North Korea.
Stephen Biegun, new US nuclear envoy who was accompanying the secretary, said he offered on Sunday to meet his counterpart, Vice Foreign Minister Choe Son Hui, "as soon as possible" and they were in discussion over specific dates and location.
Things didn't go much better a day later in Beijing, where Pompeo had the bad fortune of being the first senior US official to visit the country since a blistering speech on China last week from Pence.
The Vatican's priests were expelled by North Korea long ago and state-appointed laymen officiate services.
Trump said "eventually we're going to have lots of meetings on USA soil and on their soil by the way".
Pompeo told journalists in Seoul that the leader had agreed to open up the Punggye-ri nuclear testing site to inspectors.
The Secretary of State did not meet Kim on that trip.
Kim's push for greater global recognition is also aimed at softening his image and weakening the US-led "maximum pressure" campaign.
Pompeo said they came close to finalising a date and venue for the next Kim-Trump meeting.
The two countries have, however, been in a standoff over what the term denuclearisation means.
But this time, the North Korean reaction to the talks was much more positive.
Moon said a second Trump-Kim summit could be accompanied by major diplomatic developments that could contribute to the denuclearization of the Korean Peninsula and stabilizing peace.
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