(CNN) Former New York City Mayor Michael Bloomberg came out swinging against President Donald Trump's trade policies Thursday at an appearance alongside Democratic Rep. Jim Clyburn in South Carolina.

"They're not good for us. They are not good for the rest of the world," he told a group gathered at Benedict College in Columbia.

It's not the first time Bloomberg has criticized Trump's trade policies.

"Regardless of whether you're a Republican or Democrat, this is just a failure of our government," he said in an interview last month with Bloomberg News , which he owns.

He re-registered himself as a Democrat last week and is one of many big-name Democrats who have traveled to South Carolina to introduce themselves to voters in the weeks before the midterm election.

The Trump administration has imposed tariffs on foreign steel and aluminum in order to protect those domestic industries, which it deems important for national security. Trump has also imposed tariffs on $250 billion of Chinese goods — a move the administration says is warranted because China has engaged in unfair trade practices, including intellectual property theft, for years.

While Bloomberg agrees that trade issues with China must be addressed, he has said that Trump is fighting them the wrong way. Blocking Chinese markets hurts US workers and consumers, he told Bloomberg News, citing retaliatory tariffs.

Many American business leaders have said that China's trade practices are unfair, but they object to the use of tariffs, which are paid by companies importing the products. CEOs now have to decide whether to absorb the cost or pass it on to consumers. Some may be able to find a new supplier outside of China, but that takes time.

Thousands of companies have asked the government to exclude certain products from the tariff list, claiming they cannot find another supplier outside of China for the items they need. None of their requests have been granted so far.