U.S. President Donald Trump warned on Thursday there was much more he could do that would hurt China’s economy further, showing no signs of backing off an escalating trade war with Beijing, Reuters reported.

“It’s had a big impact,” Trump said in a Fox News interview. “Their economy has gone down very substantially and I have a lot more to do if I want to do it.

“I don’t want to do it, but they have to come to the table.”

Trump said the Chinese want to negotiate but he does not believe they are ready and he told them so. He blamed previous U.S. presidents for allowing China to pursue unfair trade practices and said he had to tell Beijing, “It’s over.”

“They lived too well for too long and, frankly, I guess they think the Americans are stupid people. Americans are not stupid people. We were led badly when it came to trade,” Trump told “Fox & Friends.”

The growing trade war prompted the International Monetary Fund on Tuesday to cut its global economic growth forecasts for 2018 and 2019.