With trade negotiations resuming this week between the world’s two largest economies, relations between the United States and China look to have reached a new low.

President Donald Trump lashed out at Beijing on Tuesday and its unwillingness, according to him, to buy agriculture products, and that China continues to “rip off” the U.S.

“China is doing very badly, worst year in 27 — was supposed to start buying our agricultural product now — no signs that they are doing so,” Trump tweeted. “That is the problem with China, they just don’t come through. Our Economy has become MUCH larger than the Chinese Economy is last 3 years. My team is negotiating with them now, but they always change the deal in the end to their benefit. They should probably wait out our Election to see if we get one of the Democrat stiffs like Sleepy Joe.

“Then they could make a GREAT deal, like in past 30 years, and continue to ripoff the USA, even bigger and better than ever before. The problem with them waiting, however, is that if & when I win, the deal that they get will be much tougher than what we are negotiating now … or no deal at all. We have all the cards, our past leaders never got it!”

A U.S. delegation including Treasury Secretary Steve Mnuchin and Trade Representative Robert Lighthizer arrived in Shanghai this week to restart trade talks that have been on hold for three months. Expectations for a breakthrough remain low, and Trump’s tweets sent the markets downward in morning trading Tuesday.

Meanwhile, China blamed Washington for recent violence in Hong Kong protests that are the “creation of the U.S.”

Chinese Foreign Ministry spokesperson Hua Chunyig responded to a comment by U.S. Secretary of State Mike Pompeo on Monday that he hopes “the Chinese will do the right thing” in regards to the protests.

“It’s clear that Mr. Pompeo has put himself in the wrong position and still regards himself as the head of the CIA,” Hua said, referring to Pompeo’s previous role at the intelligence agency. “He might think that violent activities in Hong Kong are reasonable because after all, this is the creation of the U.S.”

Last week, Hua said Washington should remove its “black hand” from the protests, a comment the State Department deemed “ridiculous.”

Beijing has long blamed unrest in Hong Kong, which was a British territory until 1997, on foreign influence. Those complaints have ramped up along with unrest in the Chinese territory where the U.S. and European countries have urged China to respect the rights of Hong Kong protesters fighting for democracy.

During her comments Tuesday, Hua said some protesters looked American and were waving the U.S. flag.

“In the media footage of the violent protests, many U.S. faces appeared among the protesters, even U.S. national flags at one point,” Hua said. “What role does the U.S. play exactly in the recent Hong Kong protests? The U.S. owes the world an explanation on this matter.”