China tariff war a little squabble: Trump

US President Donald Trump insists trade talks with China have not collapsed and called the widening US-China tariff war "a little squabble" even as his administration readies 25 per cent duties on all remaining Chinese imports.

Expanding on a stream of optimistic early morning tweets on Tuesday about the state of talks, Trump told reporters that he has a "very good dialogue" going with China and touted his "extraordinary" relationship with Chinese President Xi Jinping.

"We have a dialogue going. It will always continue," Trump said. "But we made a deal with China ... We had a deal that was very close but then they broke it. They really did."

Trump appeared to downplay the scope of the trade war, which could lead to tariffs this (northern) summer on all trade between the world's two largest economies, raising costs and disrupting supply chains across the globe.

"We're having a little squabble with China because we've been treated very unfairly for many, many decades," Trump said, referring to US complaints about Chinese intellectual property and subsidy practices.

Stocks, which took a beating on Monday after Trump late on Friday threatened a new round of tariffs on about $US300 billion ($A432 billion) worth of remaining imports from China, gained strength after Trump's comments.

Trump earlier tweeted that a deal would happen and appealed to China to buy US farm products.

"When the time is right we will make a deal with China," Trump said. "It will all happen, and much faster than people think!"

"Hopefully China will do us the honor of continuing to buy our great farm product, the best, but if not your Country will be making up the difference," he wrote in a post addressing US farmers directly.

Trump on Monday said his administration was planning to provide about $US15 billion in aid to help US farmers whose products were targeted by Chinese retaliatory tariffs. He declined to provide details on the plan, which follows $US12 billion in US farm aid last year.

Trump also said on Monday that he expected to meet with Chinese President Xi Jinping at a G20 leaders summit in Japan in late June.

China retaliated on Monday with higher tariffs on a revised list of $US60 billion worth of US products

Some members of congress who have been supportive of Trump's tough stance on China expressed concern that the president is escalating tariffs without an exit strategy.

"Let's be blunt: it's a tax on the American consumer and the American manufacturer ... who's paying about $1.4 billion a month in new tariffs," Democratic senator Chris Coons said in an interview with MSNBC on Tuesday.

China's foreign ministry said it hoped the US does not "underestimate China's determination and will to safeguard its interests".

"My understanding is that China and the United States have agreed to continue pursuing relevant discussions. As for how they are pursued, I think that hinges upon further consultations between the two sides," Chinese foreign ministry spokesman Geng Shuang told a daily news briefing, without giving details.