Former Treasury Secretary Larry Summers called President Donald Trump’s suggestion that China is trying to devalue its currency “incredible” during a wide-ranging interview with Yahoo Finance’s Andy Serwer on Friday.

Trump has repeatedly accused China of trying to keep its currency low to make China’s exports cheaper.

During the conversation, Serwer asked Summers his thoughts on Trump’s declaration last week that the Chinese are “grand champions of currency manipulation and stealing US manufacturing jobs.”

“At a time moment when China has established a huge regulatory apparatus to stop people from selling renminbi for dollars, the suggestion that China is manipulating its currency downwards seems to me incredible,” Summers said.

While some analysts have contended China devalued the yuan in the 1990s and 2000s, others have noted that China modified its currency policy in 2005 and allowed the yuan to appreciate. These days, many analysts believe now that China is actively trying to prop up the value of its currency as private capital flees the country.

Still, Summers acknowledged that China is by no means a perfect trading partner.

“Are there subsidies that aren’t right? Things that China is doing that discriminate against US companies? Yeah, there are,” Summers said. “And I think those are things that it’s right to go after.”

Indeed, the US has gone after China for its agricultural subsidies. In September, the US government filed a complaint with the World Trade Organization claiming China was giving excess subsidies to producers of corn, rice, and wheat at the expense of American farmers. And, in November, the American Chamber of Commerce in China cited a poll of US businesses in China finding that 77% of respondents felt they’d been unjustly targeted by Chinese regulators.

Still, those issues are separate from currency manipulation, according to Summers, who noted, “Framing these issues in terms of currency manipulation seems to me many days late, and many dollars short.”

More from our interview with Larry Summers:

• Larry Summers describes 3 problems posed by business people in Washington

• Larry Summers: Infrastructure critics are ‘quite misguided’

• Larry Summers calls Trump trade talk a ‘clear negative for the industrial heartland’

• Larry Summers: Banks with high capital levels can still fail

• Larry Summers says media needs to be ‘intense, but disinterested’ Trump

Full Interview: