The move comes days after the U.S. imposed $34 billion worth of tariffs on Chinese goods.
Veteran U.S. diplomat Robert Gallucci said Trump's "tweeting on the subject of war and peace with North Korea isn't the most useful thing in the world."
The Sinuiju Cosmetics Factory is known for its special "spring fragrance."
Xi warned Mattis on Wednesday that China "cannot lose even one inch of the territory left behind by our ancestors."
Mattis is the first Pentagon chief to visit China since 2014.
It is no longer North Korea.
Russia is siding with China in a trade dispute that's also testing Washington's ties with traditional allies such as the EU, Canada and Mexico.
Beijing is keeping a close eye on which officials Washington will send.
Russia's Putin has visited China at least once a year since relations with the West collapsed over his annexation of Crimea in 2014.
Kim Jong Un "has created sort of a cushion for failure, that if the U.S. backs away, the Chinese and Russians will be behind him," 38 North's Joel Wit said.
China revealed that it feels endangered. Washington can acknowledge China's importance by seeking its help to get Kim Jong Un to the negotiating table.
"It could very well be that he's influencing Kim Jong Un. We'll see what happens," Trump said.
As many as 1 million Chinese Muslims are believed to have been detained in the camps.
China says it has "the resolve, confidence and ability" to defend its territorial integrity by reuniting Taiwan with the mainland by force.
China will begin applying an extension of the system to flights and trains to stop millions of people who have committed misdeeds.
The two leaders will meet for an "informal summit" just eight months after a tense military border standoff.
Chinese President Xi Jinping appears to be losing patience with Taiwan's ideas of independence and he's turning up the heat with military exercises.
Weibo's move has been perceived as a crackdown on ideas that do not fall in line with socialism.