President Donald Trump’s top economic adviser blamed Chinese President Xi Jinping for holding back talks aimed at easing a trade confrontation with the U.S.

K“As far as we know, President Xi at the moment does not wish to make a deal,” White House National Economic Council Director Larry Kudlow said at the CNBC Institutional Investor Delivering Alpha conference in New York on Wednesday. “I do not think President Xi, at the moment, has any intention of following through on the discussions we made.”

The trade negotiations between the U.S. and China aimed at defusing tensions have stalled, said Kudlow. Throughout it all, Trump has maintained a good relationship with Xi and they are working together to thwart North Korea’s nuclear threat, said Kudlow.

But big differences remain over trade, he said. “Xi is holding the game up,” he said. Xi’s top economic adviser, Liu He, appears willing to move forward on a deal, said Kudlow. Liu was involved in three rounds of negotiations over trade with U.S. officials in May and June.

Trump earlier this month imposed 25 percent tariffs on $34 billion of Chinese goods, with another $16 billion to follow soon. The administration has also released a list of 10 percent tariffs on an additional $200 billion of Chinese goods, which could take effect as early as next month. China retaliated on the first wave of tariffs by slapping duties on the same dollar amount of U.S. imports, and Beijing has said it’ll fight against any further U.S. actions.

Trump authorized the tariffs after an investigation he ordered by the U.S. Trade Representative’s office found that China was violating intellectual property rules and forcing American companies operating in China to hand over their technology secrets to gain access to the market.

China hasn’t “responded at all, not one basis point, to our request to do something about the theft of intellectual property and the forced divestiture of our technology,” said Kudlow.