Trump spoke positively about the outcomes of his visit, saying he hoped the two countries would work together closely to tackle challenges, and promote fair and balanced economic ties.
Trump in January criticized Toyota for importing cars to the US from Mexico.
Trump and Erdogan exchanged views on ending the crisis in Idlib as soon as possible.
Trump also revealed that he acknowledged the intention of many US Congress members, who were seeking tough punishment on Saudi Arabia over the Khashoggi incident, but indicated little willingness to echo their call.
Trump told staff from the US mission to the United Nations he wanted to know who provided information to the whistleblower, according to an audio recording provided to the Los Angeles Times by an attendee.
Trump has been mulling response to the alleged "chemical attack" that occurred in Syria on Saturday, with the possibility of US military actions against Syria looming large.
青岛排名优化
Trump's China visit to define US-China ties
Trump said, "China is very serious, and we are very serious," adding that the tariffs announced "will continue unless we make a trade deal".
Trump signaled that he was in no mood to compromise as he met with Japanese Prime Minister Shinzo Abe, who has tried to cultivate a friendly relationship with the American president.
TuSimple, a startup that makes autonomous trucks and has offices in both China and the United States, said it has teamed up with leading logistics operators in the US to build what it claimed would be the world's first autonomous freight vehicle network.